Rosette formation assays in dogs: lack of specificity of E rosettes for T lymphocytes.

The present study examined the specificity of guinea pig erythrocyte (E) and erythrocyte-antibody-complement (EAC) rosette formation assays with suspensions of canine peripheral blood lymphocytes. Neutrophils, monocytes, and lymphocytes bound EAC but not erythrocyte-antibody (EA) controls. Similarly, all three cell types formed rosettes with guinea pig E. Adherence of guinea pig E to these cells was apparently mediated by natural cytophilic antibodies present in the serum used in the suspension medium. The nonspecificity of the guinea pig E-rosette formation assay with canine lymphocytes renders the technique unreliable for the identification of thymus-derived lymphocytes in dogs.