961 MATERNAL-INFANT TRANSFER OF NON-HUMORAL IMMUNITY TO INFLUENZA IN THE MOUSE

Abstract

Evidence was sought for the transfer of influenza specific non-humoral immunity from mother to infant mouse. We studied infant mice born to 3 groups of mothers: (1) influenza immune mothers in whom influenza-specific serum antibody was suppressed by passive antibody received prior to non-lethal influenza infection (I-Ab), (2) influenza immune mothers with antibody (I+Ab) and (3) non-immune controls.I-Ab and control mothers as well as their infants showed no evidence of influenza specific serum antibody 7 days after infection. In contrast, high levels of serum antibody were found in all I+Ab mothers and infants 7 days after infection (P<0.001). After a lethal influenza challenge, no infant mortality was found in either immune group (I-Ab, I+Ab), whereas 11 of 16 infants in the control group died. Three days after lethal challenge, I-Ab infants showed a lower but not statistically different mean lung virus titer when compared to controls (P=0.11). At 7 days, lung virus titers of control infants continued to rise, while titers of I-Ab and I+Ab infants declined. Nasal virus titers of I-Ab and control infants did not differ, whereas, nasal virus titers of I+Ab infants showed a decline from day 3 through 7 after infection.We conclude that influenza specific non-serum-antibody mediated immunity is 1) transferred from mother to infant, 2) protects against death, 3) plays a role in reducing lung virus shedding and 4) has no effect on nasal virus shedding.