Lymphocyte proliferation in response to Brucella abortus 2308 or RB51 antigens in mice infected with strain 2308, RB51, or 19.

Lymphocyte proliferation to 22 protein fractions (106 to 18 kDa) of Brucella abortus 2308 or the lipopolysaccharide O-antigen-deficient mutant of 2308, strain RB51, was measured for 20 weeks after infection of mice with strain 2308, RB51, or 19. Throughout the 20-week study, the 22 protein fractions of 2308 and RB51 induced a similar pattern of proliferation when they were incubated with lymphocytes from the infected mice. In addition, during the 20 weeks, lymphocytes from all groups of infected mice exhibited the highest proliferation when the lymphocytes were incubated with 18-kDa or smaller proteins from either 2308 or RB51. Lymphocytes obtained from mice at 6 weeks after infection with strain RB51 or 19 exhibited similar proliferation to the 18-kDa proteins of S2308 or SRB51. Lymphocytes from strain 2308-infected mice did not proliferate to these proteins until 10 weeks after infection, and the responses were similar to those in strain RB51-infected mice but lower than those in strain 19-infected mice. Lymphocytes obtained from mice at 20 weeks after infection with strain 19 or 2308 proliferated to most of the 22 fractions of 2308 or RB51, which contained 106- to 18-kDa proteins. However, lymphocytes obtained from strain RB51-infected mice at 20 weeks did not proliferate to any of these fractions. These results indicate that mice infected with RB51 have less-persistent lymphocyte proliferative responses to 2308 proteins than do mice infected with 2308 or 19. In addition, all 2308 proteins that stimulate lymphocyte proliferation appear to be present in RB51.