scholarly journals MOUSE THYMUS-INDEPENDENT AND THYMUS-DERIVED LYMPHOID CELLS

1972 ◽  
Vol 136 (5) ◽  
pp. 984-1007 ◽  
Author(s):  
J.-P. Lamelin ◽  
B. Lisowska-Bernstein ◽  
A. Matter ◽  
J. E. Ryser ◽  
P. Vassalli
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Bacteriophage T4 ◽  
Surface Antigens ◽  
Lymphoid Cells ◽  
Antigen Binding ◽  
Antigenic Modulation ◽  
Neuraminidase Treatment ◽  
Lymphocyte Antigen

The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen (MSLA and BAθ) or thymus-independent (B) cell mouse-specific bone marrow-derived lymphocyte antigen (MBLA) surface antigens allowed direct proof of the different specificity of these antisera by double immunofluorescence (IF) staining with selective visualization of fluorochromes. These antisera and antisera against mouse Ig and its different types of chains were then used with technique of either double IF staining or IF combined with radioautography, allowing the following conclusions: (a) Surface Ig (sIg) was found exclusively on B cells and never on T cells, but not all B cells had sIg. Cells containing detectable amounts of Ig were MBLA+, but had less sIg than other B cells or none at all. There was evidence for the existence of a significant number of MBLA+ lymphocytes, neither bearing nor containing detectable Ig. (b) µ-Chains were the most frequent but not the only heavy chains found on spleen cells; however, it could not be decided with the technique used, if a single cell can bear more than one type of heavy chain. No cell containing γ-chains was found to bear surface µ-chains, although a very few cells containing both µ- and γ-chains were observed. (c) The antigen-binding cells detected after immunization with bacteriophage T4, bovine serum albumin, Maia squinado hemocyanin, and sheep erythrocytes were analyzed for MSLA, MBLA or sIg using double IF, a combination of IF and radioautography, or inhibition of "rosette" formation. Practically all the antigen-binding cells detected were MSLA-, MBLA+, sIg+. (d) More B cells than T cells were found among short-lived lymphoid cells labeled by repeated in vivo injections of tritiated thymidine, but the results did not support a simplified concept equating T cells to long-lived and B cells to short-lived lymphocytes. (e) Cells dividing rapidly in the lymph nodes draining the sites of immunization with various antigens were predominantly T cells 2 days after immunization and in majority B cells a few days later. (f) Incubation of lymphoid cells at 37°C with rabbit anti-mouse Ig or anti-κ chains led to complete disappearance of sIg and to decrease of MBLA ("antigenic modulation"). In the same conditions, anti-MBLA gave partial modulation of MBLA and of sIg; MBLA, however, reappeared much faster than sIg. No modulation of T cell surface antigens by the appropriate antisera was observed. Cell treatment with Pronase could remove MBLA, sIg, MSLA, and BAθ, which reappeared within a few hours. Neuraminidase treatment was without detectable effect on these antigens.

scholarly journals The Ets protein Spi-B is expressed exclusively in B cells and T cells during development.

1996 ◽  
Vol 184 (1) ◽  
pp. 203-214 ◽  
Author(s):  
G H Su ◽  
H S Ip ◽  
B S Cobb ◽  
M M Lu ◽  
H M Chen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Expression Patterns ◽  
Lymphoid Cells ◽  
Cell Maturation ◽  
White Pulp ◽  
Ets Family ◽  
T Cell Lines

Spi-B and PU.1 are hematopoietic-specific transcription factors that constitute a subfamily of the Ets family of DNA-binding proteins. Here we show that contrary to previous reports, PU.1 and Spi-B have very different expression patterns. PU.1 is expressed at high levels in B cells, mast cells, megakaryocytes, macrophages, neutrophils, and immature erythroid cells and at lower levels in mature erythrocytes. PU.1 is completely absent from peripheral T cells and most T cell lines based on sensitive RT-PCR assays. In contrast, Spi-B is expressed exclusively in lymphoid cells and can be detected in early fetal thymus and spleen. In situ hybridizations of adult murine tissues demonstrate Spi-B mRNA in the medulla of the thymus, the white pulp of the spleen, and the germinal centers of lymph nodes. Spi-B expression is very abundant in B cells and both Spi-B mRNA and protein are detected in some T cells. In situ hybridization and Northern blot analysis suggest that Spi-B gene expression increases during B cell maturation and decreases during T cell maturation. Gel-retardation experiments show that Spi-B can bind to all putative PU.1 binding sites, but do not reveal any preferred Spi-B binding site. Finally, both PU.1 and Spi-B function as transcriptional activators of the immunoglobulin light-chain enhancer E lambda 2.4 when coexpressed with Pip (PU.1-interaction partner) in NIH-3T3 cells. Taken together, these data suggest that differences in patterns of expression between Spi-B and PU.1 distinguish the function of each protein during development of the immune system.

scholarly journals A natural model of immunologic tolerance. Tolerance to murine C5 is mediated by T cells, and antigen is required to maintain unresponsiveness.

1982 ◽  
Vol 156 (2) ◽  
pp. 567-584 ◽  
Author(s):  
D E Harris ◽  
L Cairns ◽  
F S Rosen ◽  
Y Borel
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Lymphoid Cells ◽  
Immunologic Tolerance ◽  
Secondary Response ◽  
Spleen Cells ◽  
Physiological Concentration ◽  
Significant Drop ◽  
Natural Form

A unique experimental model is described, where natural immunologic tolerance to a well-defined soluble native antigen (murine C5) is examined in congenic strains of mice that differ only by the presence or the absence of C5. A highly sensitive hemolytic assay was developed to detect nanogram amounts of C5 as well as an assay of anti-C5 inhibition of C5 hemolytic activity. The latter was more sensitive than immunodiffusion. Two reciprocal approaches were used to study the cellular basis of tolerance in irradiated hosts of either strain. In the first, lymphoid cells from either strain were transferred to irradiated B10.D2OSN hosts that were lacking C5 and so would not hinder detection of anti-C5 antibody upon challenge with murine C5. Second, lymphoid cells from either strain were transferred to irradiated B10.D2NSN hosts, whose native C5 provided the antigenic stimulus. The immune response of whole nonadherent spleen cell suspension as well as mixtures of T and B cells (separated on the basis of surface immunoglobulin) from either strain were studied. In addition, the duration of tolerance and the antigen requirement to maintain it in irradiated C5-deficient hosts repopulated with C5-sufficient spleen cells was examined. The positive control of irradiated C5-deficient hosts repopulated with syngeneic spleen cells showed a primary and secondary response to immunization. In contrast, C5-sufficient spleen cells failed to respond both in the primary and the secondary response. Because the unresponsiveness was not caused by antigen carryover and was not antigen specific, it represents central tolerance. In C5-sufficient irradiated hosts (where immunization was not required and antigen was present in natural form and physiological concentration), transfer of C5-deficient cells mediated a drop in C5 levels to 10-20% of that noted in unreconstituted controls. T and B cell mixing experiments from the two strains into deficient or sufficient hosts demonstrated that tolerance is T cell dependent and that C5-sufficient or -deficient B cells could cooperate with nontolerant C5-sufficient T cells to produce significant anti-C5 antibody or mediate a significant drop in C5 levels. In addition, the presence of antigen was necessary to maintain tolerance. In conclusion, these results show that (a) natural tolerance to C5 is an active process that is T cell dependent and requires the presence of antigen; (b) in this natural model, clonal abortion does not seem to occur; and (c) both tolerant and nontolerant B cells retain the capacity to produce autoantibody.

scholarly journals Dynamic BH3 Profiling As Pharmacodynamic Biomarker for the Activity of BH3 Mimetics

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-6
Author(s):  
Rongqing Pan ◽  
Youzhen Wang ◽  
Shumei Qiu ◽  
Jeremy Ryan ◽  
Ensar Halilovic
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Biomedical Research ◽  
Lymphoid Cells ◽  
In Vivo Studies ◽  
Functional Assay ◽  
Bh3 Mimetics ◽  
Apoptotic Signaling

Pharmacodynamic (PD) biomarkers provide information about the pharmacologic effects of a drug on its target, i.e. to assess whether a given agent is engaging its target in the expected manner. There is currently no convenient PD marker for BH3 mimetics. BH3 profiling (BP) is a functional assay developed to measure cells susceptibility to apoptosis and cell's dependence on certain Bcl-2 anti-apoptotic proteins for survival. Dynamic BH3 profiling (DBP) measures the changes of BP signals after drug perturbations. In this study, we studied whether DBP with lymphoid cells can serve as a PD biomarker for the activity of BH3 mimetics. Using DBP and cell lines with defined dependency, we first showed that BH3 mimetics BCL201 (S55746) and S63845 are highly selective for Bcl-2 or Mcl-1, respectively. Next, we treated primary human lymphoid cells with BCL201 and then conducted DBP. We asked if pretreatment with BCL201 altered mitochondrial sensitivity to different BH3 peptides. After treatment with 1 μM BCL201, an amount consistent with achievable levels in vivo, T cell sensitivity to the Mcl-1 selective MS1 peptide, but not Bad peptide or Bfl-1 selective FS1 peptide, increased significantly, from 20% to 51%. These results suggest that BCL201 treatment increases T cell dependency on Mcl-1 and that DBP of T cells with MS1 peptide may serve as a PD marker for BCL201 activity. Similar results were also observed in B cells. Next, we conducted DBP on healthy T cells treated with S63845. T cell mitochondrial sensitivity to MS1 peptide or Bcl-xL selective HRK peptide did not change. However, the treatment increased mitochondrial sensitivity to the Bad and FS1 peptides significantly, boosting the signal from 10.2% to 57.2% and 46.8% respectively, suggesting DBP of T cells with Bad or FS1 peptides can be robust PD markers for S63845 activity. This results also indicate that S63845 treatment augmented T cell dependency on Bcl-2 and Bfl-1 for survival. Currently, we are investigating whether DBP can be used as a PD biomarker for in vivo studies. Our preliminary data suggest that DBP works well across different species (rat, mouse, and human). More importantly, DBP can detect changes in mitochondrial apoptotic signaling of ex vivo rat cells after in vivo treatment with BH3 mimetics. Conclusions: Exposure to BH3 mimetics causes changes in mitochondrial apoptotic signaling of T/B cells which are readily detectable by DBP. DBP with lymphoid cells may provide a robust PD biomarker for clinical trials testing BH3 mimetics, either as monotherapy or in combination with other agents. Disclosures Wang: Novartis Institutes for Biomedical Research: Current Employment. Qiu:Novartis Institutes for Biomedical Research: Current Employment. Halilovic:Novartis Institutes for Biomedical Research: Current Employment, Current equity holder in publicly-traded company.

A Profile of 648 Signaling Network Events Identifies Cell Subsets with Diverse, Abnormal Responses to Lymphocyte Stimuli within Follicular Lymphoma Tumors.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 356-356 ◽  
Author(s):  
Jonathan M. Irish ◽  
Faye Y. Hsu ◽  
Jeff P. Sharman ◽  
Roch Houot ◽  
Joshua D. Brody ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Cell Survival ◽  
Signaling Network ◽  
Lymphoid Cells ◽  
Network Activity ◽  
T Cell Subsets

Abstract Signal transduction plays a key role in cell survival, and changes to signaling are frequently implicated in tumor initiation and progression. We sought to identify abnormal variation in signaling network activity within primary tumor samples obtained prior to treatment from patients with follicular lymphoma (FL). We previously showed that altered B cell receptor (BCR) signaling distinguishes tumor B cells from the non-malignant host B cells in FL tumors. Here we extend this approach and use flow cytometry to measure 648 signaling events in live lymphoid cells from more than 25 lymphoma specimens and healthy controls. We combined 9 previously identified BCR stimulation conditions with inputs from CD40, interleukin 4, interferons (IFNs), and more than 10 other environmental cues that govern the development and activity of lymphocytes. Fluorescent cell barcoding allowed simultaneous staining and analysis of phospho-protein activation under all 27 stimulation conditions within a single tube. The activation of key phospho-protein nodes throughout lymphocyte signaling networks, including Syk, Erk1/2, Btk, Src family kinases, cCbl, p38, NFkB, Akt, Stat1, Stat3, Stat6, and Stat5, was measured under each of the 27 stimulation conditions. Measurements of phospho-protein responses to stimulation were combined with detection of the Bcl-2 oncogene, B and T cell lineage markers in each cell. This panel allowed us to characterize signaling in the heterogeneous cell subsets found within each patient’s tumor sample. Tumor B cells, host tumor infiltrating T cells, non-malignant B cells were all distinguished by contrasting signaling profiles. In some cases, subsets of tumor B cells with differences in signaling network topology were observed within the tumor B cell population. This result suggests that signaling can distinguish between tumor sub-clones and could be used to measure tumor heterogeneity. As previously reported, little variation in signaling was observed among healthy peripheral blood B and T cell samples from different individuals. Abnormally low host T cell signaling was commonly observed within the tumor infiltrating T cells infiltrating FL tumors. Further analysis of tumor T cell subsets indicated that a high proportion of infiltrating T cells expressed CD4 and FoxP3. Taken together, these results support the hypothesis that FL tumor B cells promote suppressed signaling in the T cells of the patient and may modulate the immune response against the tumor. In FL tumor B cells, BCR and IFN signaling frequently triggered Stat5 phosphorylation, but not Stat1 phosphorylation. These results are consistent with the hypothesis that Stat5 initiates genetic programs that support cancer cell survival and proliferation, whereas Stat1 promotes immunogenicity and cooperates with the p53 tumor suppressor protein. In contrast with healthy B cells, loss of the response to CD40L, altered PKC signaling, and variable responses to BCR crosslinking were all seen in FL tumor B cells. The patterns of abnormal signaling we observed in tumor B cells and tumor infiltrating T cells suggest that measuring the activity of key signaling network nodes can identify targets for therapeutic attention in FL.

scholarly journals CHARACTERIZATION OF SPLENIC LYMPHOID CELLS IN FETAL AND NEWBORN MICE

1973 ◽  
Vol 138 (3) ◽  
pp. 557-573 ◽  
Author(s):  
Patricia G. Spear ◽  
Ai-Lan Wang ◽  
Urs Rutishauser ◽  
Gerald M. Edelman
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cellular Proliferation ◽  
Immunological Response ◽  
Qualitative Change ◽  
Lymphoid Cells ◽  
Antigen Binding ◽  
Newborn Mice ◽  
Quantitative Changes

In order to clarify the cellular events that precede the onset of immunological competence in the mouse, we have characterized and quantitated the lymphoid cells of the spleen as a function of age. Our results show that T cells and B cells both appeared in the spleens of Swiss-L mice as early as the 15th-16th day of gestation. Antigen-binding cells specific for each of three different antigens were also first detected during this same 24 h interval. The B cells and three varieties of antigen-binding cells increased in number rapidly and in parallel until about 1 wk after birth. The T cells, which were more numerous than B cells at first, increased in number somewhat more slowly. Coincident with the onset of response to antigen, there was a further increase in B cell numbers and a decrease in the T cell to B cell ratio. The capacity to respond to antigen by cellular proliferation and synthesis of antibody did not arise until about 2 wk after birth although there were no quantitative changes in the total numbers of T cells, B cells, and antigen-binding cells between 1 and 2 wk of age. Some qualitative change, such as the functional maturation of an antigen-reactive cell, may be required during this interval for the onset of this immunological response. Although the numbers of antigen-binding cells present in fetuses and young animals were smaller than in adults, we have as yet been unable to detect any restriction in the variety of specificities that can be expressed in fetuses, either in the kinds of antigens bound or in the range of avidities with which a single antigen is bound.

scholarly journals Expression of Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases in Reactive and Neoplastic Lymphoid Cells

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1708-1715 ◽  
Author(s):  
Maryalice Stetler-Stevenson ◽  
Adnan Mansoor ◽  
Megan Lim ◽  
Paula Fukushima ◽  
John Kehrl ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Lines ◽  
Peripheral Blood ◽  
Cell Lineage ◽  
Lymphoid Cells ◽  
High Grade ◽  
Gelatinase B ◽  
T Cell Lines

We have studied the expression of gelatinase A, gelatinase B, interstitial collagenase, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in reactive lymphoid cells, as well as in a series of cell lines derived from neoplasms of B- and T-cell lineage. Using both Northern blot analysis and zymography, gelatinase B activity was detected by zymography in two Burkitt cell lines and in a tonsillar cell suspension, while gelatinase A and interstitial collagenase activities were not detected by either method. TIMP-1 expression was demonstrated by Northern blot analysis in the multipotential neoplastic K-562 cell line, the high grade Burkitt's B-cell lymphoma lines, isolated tonsillar B cells and at low levels in peripheral blood T cells, but was not expressed in any of the neoplastic T-cell lines or isolated peripheral blood B cells. In contrast, TIMP-2 expression was restricted to tissues containing cells of T-cell lineage with high levels being observed in the neoplastic T-cell lines and lower levels in normal peripheral blood T cells and hyperplastic tonsil. Expression of TIMP-1 and TIMP-2 was confirmed at the protein level by reverse zymography and immunofluorescence assays using antihuman TIMP polyclonal antibodies. Expression of gelatinase B by the high grade B-cell Burkitt's lymphoma cell lines is consistent with previous findings in large cell immunoblastic lymphomas and indicates that this enzyme may play an important role in high grade non-Hodgkin's lymphomas. TIMP expression correlated with cell lineage in that TIMP-1 was primarily observed in B cells and TIMP-2 was restricted to T cells.

scholarly journals Expression of Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases in Reactive and Neoplastic Lymphoid Cells

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1708-1715 ◽  
Author(s):  
Maryalice Stetler-Stevenson ◽  
Adnan Mansoor ◽  
Megan Lim ◽  
Paula Fukushima ◽  
John Kehrl ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Lines ◽  
Peripheral Blood ◽  
Cell Lineage ◽  
Lymphoid Cells ◽  
High Grade ◽  
Gelatinase B ◽  
T Cell Lines

Abstract We have studied the expression of gelatinase A, gelatinase B, interstitial collagenase, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in reactive lymphoid cells, as well as in a series of cell lines derived from neoplasms of B- and T-cell lineage. Using both Northern blot analysis and zymography, gelatinase B activity was detected by zymography in two Burkitt cell lines and in a tonsillar cell suspension, while gelatinase A and interstitial collagenase activities were not detected by either method. TIMP-1 expression was demonstrated by Northern blot analysis in the multipotential neoplastic K-562 cell line, the high grade Burkitt's B-cell lymphoma lines, isolated tonsillar B cells and at low levels in peripheral blood T cells, but was not expressed in any of the neoplastic T-cell lines or isolated peripheral blood B cells. In contrast, TIMP-2 expression was restricted to tissues containing cells of T-cell lineage with high levels being observed in the neoplastic T-cell lines and lower levels in normal peripheral blood T cells and hyperplastic tonsil. Expression of TIMP-1 and TIMP-2 was confirmed at the protein level by reverse zymography and immunofluorescence assays using antihuman TIMP polyclonal antibodies. Expression of gelatinase B by the high grade B-cell Burkitt's lymphoma cell lines is consistent with previous findings in large cell immunoblastic lymphomas and indicates that this enzyme may play an important role in high grade non-Hodgkin's lymphomas. TIMP expression correlated with cell lineage in that TIMP-1 was primarily observed in B cells and TIMP-2 was restricted to T cells.

scholarly journals L2C Guinea Pig Lymphatic Leukemia: A "B" Cell Leukemia

Blood ◽  
1972 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
E. M. Shevach ◽  
L. Ellman ◽  
J. M. Davie ◽  
I. Green
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Guinea Pig ◽  
B Cell ◽  
B Lymphocyte ◽  
Lymphoid Cells ◽  
Cell Mediated Immunity ◽  
Lymphatic Leukemia

Abstract Lymphoid cells of the immune system can be divided into two functional compartments. The thymus derived population, "T" cells, is responsible for cell mediated immunity. The bone marrow derived population, "B" cells, is responsible for antibody production. Although these two populations are functionally different, it has not yet been possible to distinguish them morphologically. Recent experimental work in the mouse has shown that the B cells bear easily detectable immunoglobulin. The T cells can be distinguished by the isoantigen, theta. The B or T cell origin of the lymphocytes of human or animal leukemia has received little attention. In the present study, we have examined the functional and morphologic properties of a guinea pig lymphatic leukemia L2C. L2C cells secrete T2 immunoglobulin and also bear this immunoglobulin on their surface. L2C cells have the recently described lymphocyte receptor for antigen-antibody-complement complexes (found on normal B lymphocytes). Finally, the L2C cell fails to be stimulated in vitro by mitogens capable of stimulating thymus-derived lymphocytes. Thus, the L2C cell appears to be of B lymphocyte origin. The availability of a large number of pure B lymphoid cells will provide a useful tool for the study of the cellular receptors of lymphoid cells and for the preparation of antisera specific for the T cell and B cell populations. The application of the techniques described in this paper to classify other lymphoid neoplasms as to their T or B cell origin may lead to both theoretic and therapeutic advances.

scholarly journals Specific binding of K- and I-region products of the H-2 complex to activated thymus-derived (T) cells belonging to different Ly subclasses.

1976 ◽  
Vol 144 (6) ◽  
pp. 1545-1553 ◽  
Author(s):  
Z Nagy ◽  
B E Elliott ◽  
M Nabholz
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
T Cell ◽  
B Cells ◽  
Specific Surface ◽  
Specific Binding ◽  
Surface Antigens ◽  
Background Levels ◽  
Lymph Node Cells ◽  
Nylon Wool

Responder cells [C57BL/6J X A.TL)F1 lymph node cells depleted of bursa equivalent-derived (B) cells by filtration through nylon wool columns] were activated against incompatible K-region and I-region products together under conditions where these antigens are presented on separate stimulator cells. The resulting T blasts were stained with different concentrations of antisera directed against incompatible stimulator K-region or I-region products, or both. We obtained results that strongly suggest that in these cultures each activated responder blast stains with antiserum directed against either K-region or I-region products, but not both. Responder blasts from the same cultures were treated with antiserum and complement (C) directed against either Ly-1.2 or Ly-2.2 T-cell-specific surface antigens. Anti-Ly-1.2 serum and C specifically eliminates virtually all responder blasts staining with antiserum directed against stimulator I-region products; whereas anti-Ly-2.2 serum reduces to background levels the proportion of cells staining with antiserum against stimulator K-region products. The results obtained suggest that T cells binding stimulator K-region and I-region products, respectively, belong to two different subclasses distinguishable by their Ly phenotypes. Possible explanations for this association of T- cell subclass and specificity are discussed.

scholarly journals IMMUNOGLOBULIN AND OTHER SURFACE ANTIGENS OF CELLS OF THE IMMUNE SYSTEM

1971 ◽  
Vol 134 (4) ◽  
pp. 815-832 ◽  
Author(s):  
Toshitada Takahashi ◽  
Lloyd J. Old ◽  
K. Robert McIntire ◽  
Edward A. Boyse
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
B Cells ◽  
B Cell ◽  
Surface Antigens ◽  
Mouse Serum ◽  
Phenotypic Change ◽  
Cytotoxicity Test ◽  
Antigenic Modulation

Immunoglobulins (Ig) on cells of the immune system: The cytotoxicity test, with class-specific and type-specific anti-Ig sera, identifies κ and µ determinants on mouse lymphocytes. The proportion of κ+ cells is characteristic for each source of cells: 30% of bone marrow cells, 40% of cells from peripheral lymph nodes, 45% of lymphocytes from peripheral blood or peritoneal cavity, and 50% of spleen cells. No Ig was demonstrable on thymocytes or on leukemia cells (most of which arise from thymus-derived [T] cells). Cytotoxicity tests were performed on various myelomas secreting different Ig; the only positive reactions were given by κγ1 myelomas (all four κγ1 myelomas tested were sensitive to both anti-κ and anti-γ1). Hemolytic plaque-forming cells (PFC) of IgG type had no demonstrable surface Ig, but a proportion of IgM PFC were κ+µ+. Virtually all rosette-forming cells (RFC) have surface Ig, more than 90% of them being inhibited by anti-κ, 50% by anti-µ, and 10–30% by antisera to other heavy chains. Anti-λ sera gave no positive reactions with any cell type, which is in keeping with the low level of this light chain in mouse serum. Ig and other differentiation antigens as markers for T and B cells: Thymocytes are hallmarked by the alloantigens TL, θ, and the Ly series, and it is generally held that extrathymic lymphoid cells that bear them are derived from thymocytes. There is one alloantigen marker for the thymus-independent (B) cell, and that is PC, which appears late in differentiation. (The mouse-specific lymphocyte (MSLA) and mouse-specific bone marrow-derived lymphocyte (MBLA) antigens recognized by heteroantisera, not used in the present study, are other candidates for T and B cell markers.) Making use of antisera to these surface antigens to inhibit the function of cells that carry them, we find the following: Approximately 30% of RFC, 60% of IgM PFC, and 90% of IgG are PC+ and so are identified as B cells. No T markers were demonstrable on these cell populations. Thus if T cells do become RFC or PFC they presumably lose their T surface markers in the process (cf. the quantitative reduction of T markers accompanying the thymocyte → lymphocyte transition). Cells that have the potential to initiate graft-versus-host (GVH) reactions have the T cell surface phenotype θ+Ig-. Adoptive transfer of thymus-dependent antibody-forming capacity (response to sheep erythrocytes) required θ+ cells but transfer of a thymus-independent immune response to Brucella antigen did not. Cells with surface Ig were involved in both types of adoptive transfers. Thus the presently available T markers do not provide evidence for T cells carrying surface Ig. Suppression of the Ig phenotype by antibody: antigenic modulation? A phenotypic change from Ig+ to Ig- occurs when Ig+ lymphocytes or myeloma cells are incubated with anti-Ig sera in vitro in the absence of complement (C). As with antigenic modulation in the TL system, which it resembles, this phenomenon is temperature dependent and in the case of lymph node cells (LNC) can be inhibited by high doses of actinomycin D.

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