ALLOANTIBODIES AGAINST A AND B BLOOD TYPES IN CATS

This study characterizes the naturally occurring feline alloantibodies against A and B blood type. All examined type-A and type-B cats had n aturally occurring antibodies against erythrocytes of the opposite blo od type. In order to determine the class of immunoglobulins, sera from cats were analyzed using incubation with 2-mercaptoethanol (2-ME), im munoprecipitation, and gel filtration. Type-A cats had weak agglutinin s of the IgM class and weak hemolysins which consisted of approximatel y equal parts of IgG and IgM class. Type-B cats had strong hemagglutin ins and hemolysins mostly of the IgM class. Colostral antibodies were detectable in newborns as early as 4 h after birth and their own alloa ntibody production started at 6-8 weeks of age. The presence of natura lly occurring alloantibodies, in particular the anti-A alloantibodies, renders cats susceptible to clinical incompatibility reactions.