For example, both CD4+ T lymphocytes and B lymphocytes are required to control infection with B. melitensis in mice following i.p. inoculation while only α/β T lymphocytes (either CD4+ or CD8+) are required for control following intranasal infection (Mambres et al., 2016; Demars et al., 2019). The gene discussed is CD8A; the disease is infection.