Immunisation of Labeo rohita with Antigenic preparation of Aphanomyces invadans

Aphanomyces invadans is an important fungal pathogen infecting freshwater and brackishwater fishes. In the present study, an attempt has been made to determine the effect of immunisation in Labeo rohita advanced fingerlings against A. invadans infection. The efficacy of the immunisation was evaluated by challenge with A. invadans as well as quantification of antibody level by ELISA. Following an initial immunisation in conjunction with adjuvant, the fish were given a booster dose after 35 days. After 14 and 28 days of the booster injection, blood was collected from the immunised rohu for monitoring the antibody level. The fish were also challenged with A. invadans zoospores to determine the relative percent survival. The immunised fish had significantly higher antibody level after 14 days of booster injection as compared to the control fish. However, the antibody level after 28 days of booster injection was not significantly different from the control fish. More importantly, similar to control fish, 100% mortality was observed in the immunised fish challenged after 14 and 28 days of booster immunisation. Therefore, it can be concluded that it may not be suitable to induce protective immunity following immunisation with conventional antigenic preparations.

Influence of Bacillus anthracis 34F2 Sterne Antigen Preparations in Combination with Cobaltarabinogalactan on the Subpopulation Structure of B-lymphocytes (Communication 2)

Study of Bacillus anthracis 34F2 Sterne antigenic preparation S-2 and its combined use with nanostructured cobalt-arabinogalaktan (Со-АG) is presented. The ability of these preparations to stimulate proliferation and differentiation of B-lymphocytes is demonstrated. However, content of the B-lymphocyte circulating subpopulations depends on the time of observation. Co-AG exhibits adjuvant properties enhanced the immunogenic features of the S-2 B. anthracis 34F2 Sterne that may indicate its availability as an adjuvant in the construction of chemical vaccines.

Excretion-secretion products and proteases from live Sporothrix schenckii yeast phase: immunological detection and cleavage of human IgG

Antigenic preparations from Sporothrix schenckii usually involve materials from mixed cultures of yeast and mycelia presenting cross-reactions with other deep mycoses. We have standardized pure yeast phase with high viability of the cells suitable to obtain specific excretion-secretion products without somatic contaminations. These excretion-secretion products were highly immunogenic and did not produce noticeable cross-reactions in either double immunodiffusion or Western blot. The antigenic preparation consists mainly of proteins with molecular weights between 40 and 70 kDa, some of them with proteolytic activity in mild acidic conditions. We also observed cathepsin-like activity at two days of culture and chymotrypsin-like activity at four days of culture consistent with the change in concentration of different secreted proteins. The proteases were able to cleave different subclasses of human IgG suggesting a sequential production of antigens and molecules that could interact and interfere with the immune response of the host.

Development of an Enzyme-Linked Immunosorbent Assay for Serotyping Ureaplasma urealyticum Strains Using Monoclonal Antibodies

ABSTRACT Ureaplasma urealyticum comprises 14 serotypes. The existing serotyping methods all use polyclonal antibodies. These methods are time-consuming and labor-intensive, and they cannot always be performed on primary isolates; in addition, the results are difficult to interpret. We developed a new enzyme-linked immunosorbent assay (ELISA) method using serotype-specific monoclonal antibodies (MAbs) to enable the serotyping of U. urealyticum isolates from primary broth cultures. Each of the 14 serotype reference strains was tested against 14 selected MAbs. Homologous reactions were very strong, while heterologous reactions were negligible. Three cross-reactions were observed: MAb 5 cross-reacted with serotype 2, MAb 14 cross-reacted with serotype 3, and MAb 8 cross-reacted with serotype 13. Despite the cross-reactions observed, all the serotype reference strains ofU. urealyticum could be identified and differentiated using a combination of MAbs. Reproducibility was analyzed with a fractionated antigenic preparation and with several freshly prepared antigens of the same strain. No significant interrun variation was found with the fractionated antigen, but significant variations in optical density (OD) values were found when freshly prepared antigens were tested. However, the variation in OD values did not influence the overall interpretation of the ELISA: reactions with homologous MAbs were always prominent compared to those of the negative controls. This newly developed ELISA using MAbs seems promising for serotyping of U. urealyticum clinical isolates.