Effects of three antigens extracted from Vibrio vulnificus on the immunological protection of Nibea albiflora

Nibea albiflora was immunized by intraperitoneal injection with either Lipopolysaccharide (LPS) or outer membrane protein (OMP) extracted from Vibrio vulnificus or formalin killed Vibrio vulnificus (FKC). The influence of the three antigens on the immunological function of Nibea albiflora was determined at different time points following the injection by testing the agglutinating antibody titers of the serum, lysozyme activity of the serum, phagocytic activity of the blood and the relative survival percentage. The results showed that the three antigens have higher immunogenicity and antigenicity than the control group(injection with sterile saline). The agglutinating antibody titers of the immune challenged groups increased quickly, and were highest on the day 28. The lysozyme activity and phagocytic activity were raised significantly (P<0.01), reaching their top value on day 21, and then the index gradually reduced. The immunological indexes of three immune groups were higher than the control group (P<0.05). The agglutinating antibody titers of the LPS group or the OMP group were lower than the control group, but the relative survival percentage was adverse when challenged with a Vibrio vulnificus infection. The order of relative survival percentage was group LPS>OMP>FKC>Control.