VITAMIN-A-DEFICIENCY IMPAIRS SOME ASPECTS OF THE HOST RESPONSE TO INFLUENZA-A VIRUS-INFECTION IN BALB C MICE/

We examined the impact of vitamin A deficiency on the host response to an acute, viral infection of the respiratory tract by infecting BALB/ c mice with a mouse-adapted strain of influenza A virus. Several indic ators of the severity of infection were examined, including the rate o f virus clearance from the lungs, the extent of inflammatory lesions, and percentage of survival. None of these was affected by vitamin A de ficiency. Following the acute phase of infection, however, the regener ation of normal, respiratory epithelium was impaired and adenomatoid, metaplastic lesions developed within inflammatory foci in the lungs of deficient animals. The antibody response to infection was also charac terized: the influenza A-specific immunoglobulin A (IgA) response in t he respiratory tract was markedly decreased by vitamin A deficiency, b ut tracheal and lung lavage IgG titers were not affected. The serum Ig M and IgG responses, and the serum hemagglutination-inhibition respons e, were also diminished by vitamin A deficiency. Decreased mucosal IgA titers and impaired regeneration of normal respiratory epithelium cou ld impair recovery from a primary infection and increase susceptibilit y to opportunistic secondary infections.