Active Replication at (Almost) No Cost

Author(s):  
Andre Martin ◽  
Christof Fetzer ◽  
Andrey Brito
Keyword(s):  
Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 606
Author(s):  
Ieva Rinkūnaitė ◽  
Egidijus Šimoliūnas ◽  
Daiva Bironaitė ◽  
Rasa Rutkienė ◽  
Virginija Bukelskienė ◽  
...  

Parvovirus B19 (B19V) is a widespread human pathogen possessing a high tropism for erythroid precursor cells. However, the persistence or active replication of B19V in endothelial cells (EC) has been detected in diverse human pathologies. The VP1 unique region (VP1u) of the viral capsid has been reported to act as a major determinant of viral tropism for erythroid precursor cells. Nevertheless, the interaction of VP1u with EC has not been studied. We demonstrate that recombinant VP1u is efficiently internalized by rats’ pulmonary trunk blood vessel-derived EC in vitro compared to the human umbilical vein EC line. The exposure to VP1u was not acutely cytotoxic to either human- or rat-derived ECs, but led to the upregulation of cellular stress signaling-related pathways. Our data suggest that high levels of circulating B19V during acute infection can cause endothelial damage, even without active replication or direct internalization into the cells.


1962 ◽  
Vol 115 (3) ◽  
pp. 475-489 ◽  
Author(s):  
Jacob Fong ◽  
Dennis Chin ◽  
Sanford S. Elberg

Studies of passive transfer of cellular resistance, as manifested by refractoriness to necrotization with virulent tubercle bacilli, have shown that immune histiocytes or immune lymphocytes were effective transferring agents; immune polymorphonuclear leucocytes and immune serum as well as comparable cells from normal animals lacked this capacity. Comparisons of immune histiocytes and immune lymphocytes showed that the former cells were more efficient; this was indicated by (a) the smaller numbers of immune histiocytes needed for passive transfer, (b) the longer duration of cellular resistance in recipients given histiocytes than in those given lymphocytes, (c) the greater capacity of histiocytes to effect serial passive transfer, and (d) the ability of histiocytic but not lymphocytic lysates to transfer cellular resistance. Experiments to establish the mechanism of passive transfer of cellular resistance showed that there was no active induction of resistance in recipients through transfer of bacillary antigens contained in immune histiocytes; in fact, the results of serial passive transfers with immune histiocytes suggested an active replication of the "cell resistance factor."


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