We found that the percentage of infiltrating Fo B cell-expressing MHC II (Figure 9A) in TNF-/- mice was delayed and significantly lower as early as week 1 after infection in BTNF-/- and TNF-/- mice compared with the TNFf/f mice; moreover, no significant difference was seen at week 2 post-infection in any mouse strains. The gene discussed is TNF; the disease is infection.