Infected cats develop antibodies and kittens appear to be protected initially for the first one or two months of life by maternally derived antibodies [Wills, 1986].
The nature of the protective immune response to Chlamydophila infection is uncertain. However cellular immune responses are believed to play a crucial role in protection [Longbottom & Livingstone, 2004]. The major outer membrane proteins (MOMPs] and polymorphic outer membrane proteins (POMPs) are important targets for protective immune responses in other species [Longbottom & Livingstone, 2004] and have been shown to exist in the cat [Harley et al 2007].