CD4 and allergic asthma: As both αβ+CD4+ T cells (4) and γδ+ T cells (49) have been implicated in the development of allergic asthma in mice models, we next compared the ability of wild-type, γδ−/−, TAP1−/− (CD8+ T cells deficient), and MHCII−/− (CD4+ T cells deficient) C57BL/6 mice sensitized with Alt to control i.n. B. melitensis infection.