Association of HL-A 5 and immune responsiveness in vitro to streptococcal antigens

Lymphocytes, from randomly selected individuals having normal immune function, when incubated in vitro with varying concentrations of streptococcal antigens, responded in three ways: (a) response over the entire antigen concentration range, i.e., responders; (b) low response to only the highest antigen concentrations; and (c) no response at any antigen concentration. Frequency distribution analysis of these groups indicated that a significant association occurred between the ability to respond and HL-A 5.