Antigen specificity and frequency of autologous and allogeneic helper T cells in the in vitro production of antibody against influenza virus by human blood lymphocytes
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Media type:
E-Article
Title:
Antigen specificity and frequency of autologous and allogeneic helper T cells in the in vitro production of antibody against influenza virus by human blood lymphocytes
Contributor:
Smith, Caroline M.;
Callard, Robin E.
Published:
Wiley, 1982
Published in:
European Journal of Immunology, 12 (1982) 7, Seite 558-563
Description:
AbstractThe frequency of antigen‐specific helper T cells in human peripheral blood mononuclear cells was determined by limiting dilution analysis of specific in vitro antibody responses to influenza virus A/X‐31 (A‐H3N2). Limiting numbers of irradiated E rosette‐forming (E+) (T) cells were added to a constant number of syngeneic non‐rosette‐forming (E−) (“B”) cells and their ability to support production of antibody to influenza virus determined. The frequency of T helper cells was then calculated by a Poisson distribution analysis and found to range between 0.78 × 10−5 and 2.86 × 10−5. Specific antibody production can be obtained in this system from allogeneic combination of E− and E+ cells provided that the added E+ cells are irradiated to abrogate alloactivated T suppressor effects. Limiting dilution analysis applied to determine the frequency of helper T cells under these conditions showed that in most, but not all, cases the frequency of T helper cells was higher in allogeneic combinations. This result could be interpreted as showing an increase in the number of activated specific T helper cells, due perhaps to a positive allogeneic effect. On the other hand, it could also be explained by the alloactivation of an entirely different subset of nonspecific helper cells, or by the production of a nonspecific allogeneic helper factor. The specificity of T cell help in allogeneic combinations was therefore examined by adding limiting numbers of E− cells to a fixed number of E− cells and simultaneously challenging with two non‐cross‐reacting influenza viruses A/X‐31 and B/HK. Under these conditions, individual cultures produced antibody to A/X‐31, B/HK or both. The frequency of cultures producing antibody to both viruses was as predicted for the chance occurrence of specific helper T cells for both antigens being present in the same culture. The fact that a significant number of individual cultures made antibody to only one antigen in both autologous and allogeneic combinations showed that T cell help was antigen‐specific in both situations. Thus, for human in vitro antibody responses, antigen‐specific T cell help can be obtained across a major histocompatibility (complex) barrier.