ROLE OF THE B-CELL RESPONSE IN RECOVERY OF MICE FROM PRIMARY INFLUENZA-VIRUS INFECTION

Recovery from influenza virus infection has long been known to require an intact T-cell compartment. More recent studies revealed that CD8 a nd CD4 T cells can promote recovery through independent mechanisms. Th e CD4 T-cell-dependent recovery process appears to operate primarily t hrough promotion of the T-dependent antibody response as B-cell defici ent mu MT mice cannot recover from infection if they have been deplete d of CD8 T cells. The potential therapeutic activity of the B-cell res ponse was further studied by transfer of antibodies into infected SCID mice. At the dose of 200 mu g/mouse, most antibodies (of IgG2a isotyp e) to the viral transmembrane protein HA cured the infection, while th ose to the transmembrane proteins NA and M2 suppressed virus titers in the lung but failed to dear the infection. The ability of passive ant ibody to resolve the infection was closely related to its prophylactic activity, suggesting that neutralization of progeny virus (VN) played an important role in the process of virus clearance in vivo, while re action of antibodies with infected host cells contributed to but was i nsufficient, on its own, for cure. HA-specific antibodies of IgM and I gA isotypes were therapeutically ineffective against pulmonary infecti on, presumably because of a preferential delivery into the upper respi ratory tract, while IgG exhibited highest activity against pulmonary a nd minimal activity against nasal infection. B cells appear to be of s imilar importance for recovery from primary infection as CD8 T cells.