COMPARISON OF METHODS CELLULAR IMMUNITY DETECTION TO MUMPS VIRUS

Abstract Vaccination against the mumps virus has significantly reduced, but not eliminated, the incidence of this infection. Periodically, there are increases in the incidence even among populations with high vaccination coverage. Immunity to the mumps virus is most often assessed by the serum level of specific antibodies, but it is known that T-cell immunity is more important for antiviral protection. The aim of the study was to compare two methods for assessing cellular immunity to mumps virus antigens in intact adults and those who had had this infection. The study included 20 adults who had had mumps (Group 1) and 17 people who had not had or been vaccinated against this infection (Group 2). Antibodies to the mumps virus were determined by ELISA. Cellular immunity was assessed by ELISpot and by the percentage of CD8hiCD107a+ lymphocytes after recognizing mumps virus antigens. None of the subjects in group 2 were found to have IgG antibodies or cellular immunity using the ELISpot method or the percentage of CD8hiCD107a+. In group 1, 2 of 20 subjects were found to have no IgG antibodies to the mumps virus, and 18 subjects had such antibodies at different levels. A high level of cellular immunity to the mumps virus in 10 subjects (9.44±1.27) was detected by ELISpot, and a low level was detected in another 10 subjects (3.44±0.54). Based on CD107a expression on CD8hi lymphocytes, cellular immunity to the mumps virus was not detected in 4 out of 20 individuals, but antibodies to this virus were detected; another 4 individuals had a low level (2.35 (1.9-2.86)%), and 12 individuals had a high level of cellular immunity to the mumps virus (7.72-14.24)%). The cut-off level of 3.76% was calculated, dividing high and low levels of cellular immunity to mumps virus antigens with 100% sensitivity and specificity. Comparison of the ELISpot method and determination of CD107a molecule expression on CD8hi showed a negative correlation r= -0.81, which is associated, firstly, with different populations participating in cellular immunity reactions detected by these two methods, and secondly, ELISpot evaluates IFNγ producers, and CD107a expression evaluates cells that responded to antigen recognition with a cytotoxic attack. Both methods are suitable for studying cellular immunity to mumps virus antigens.