HLA-C and infection: In fact, little is known about cellular immunity following a primary AI infection in poultry, especially regarding cytotoxic T lymphocytes (CTL's).<h4>Methods</h4>In these studies, major histocompatibility complex (MHC)-defined (B2/B2) chickens were infected with low pathogenic AI (LPAI) H9N2 and clinical signs of disease were monitored over a two weeks period.