Role of different lymphocyte subsets in human anti-viral T cell cultures.

We have systematically studied uncloned human cell lines derived from anti-influenza A virus or anti-Epstein-Barr virus (EBV) bulk cultures, or from cultures highly enriched for CD4+ or CD8+ lymphocytes. The most noteworthy results are the following: (1) Anti-viral bulk cultures consisted of more than 90% of CD8+ cells in all cases. In contrast, anti-HLA cell lines are composed of approximately 50% CD8+ and 50% CD4+ cells. All of the CD8+ and CD4+ cells present in the culture were also 4B4+/2H4-. (2) In anti-viral bulk cultures, the cytolytic activity was restricted by HLA class I molecules and almost exclusively through a single HLA class I molecule. (3) Positively or negatively selected CD8+ lines showed the same restriction pattern. They grew less efficiently than bulk cultures but could be maintained in the absence of CD4+ cells. The CD4+ cells were however necessary at the beginning of the culture for the development of cytolytic anti-influenza virus CD8+ cells, whereas they were not required for the development of cytolytic anti-EBV CD8+ cells. (4) The CD4+ cell lines grew more actively than bulk cultures. A cytolytic activity for virus-infected cells was constantly detected in these culture from the third passage onward and it was always restricted by HLA class II molecules. This activity was maintained throughout the culture period. However, class II-restricted cytolytic cells were not detected during primary or secondary responses in vitro.