Abstract
The presence of C3 receptors on blood lymphocytes of yellowtail Seriola quinqueradiata was investigated by rosette forming assay. The dependence of this adherence reaction on the complement and in particular on the components of the alternative pathway was demonstrated in this experiment.
Yellowtail lymphocytes formed rosette with rabbit red blood cells (RRBC) which had been pre-incubated with fresh normal yellowtail serum. This rosette formation was inhibited by treatments of the serum with EDTA, zymosan or heating at 50°C for 20 min. Antibodies with respect to the yellowtail C3 component inhibited the attachment of the sensitised RRBC to the lymphocytes, while antibodies with respect to yellowtail IgM showed no inhibition.
On the basis of the above observations, we speculated that the RRBC adherence reaction might depend on C3 component receptors present on the lymphocyte surface membrane. This result indicated the presence of C3 receptors on yellowtail lymphocytes.
