The immune system of lizards and snakes is influenced by age, nutrition, general health, ambient temperature and season. In temperate species thymic involution and splenic follicle regression occur seasonally. Antibody production is temperature dependent. The immune system functions most efficiently within a reptile's [[Preferred optimum temperature zone]] although at a low level in comparison to birds and mammals. In captivity, lizards and snakes that are kept below their [[Preferred optimum temperature zone|POTZ]] are immunocompromised and are therefore predisposed to infection with opportunistic pathogens.
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The immune system of lizards and snakes is influenced by age, nutrition, general health, ambient temperature and season. In temperate species thymic involution and splenic follicle regression occur seasonally. Antibody production is temperature dependent. The immune system functions most efficiently within a reptile's [[Preferred optimum temperature zone|preferred optimum temperature zone]] although at a low level in comparison to birds and mammals. In captivity, lizards and snakes that are kept below their [[Preferred optimum temperature zone|POTZ]] are immunocompromised and are therefore predisposed to infection with opportunistic pathogens.