DETERMINATION OF THE EFFECTIVE DOSE OF VIRUS FOR THE DETERMINATION OF VIRUS-NEUTRALIZING ANTIBODIES FROM THE BLOOD SERUM OF ANIMALS VACCINED AGAINST COW-POX

Assessment of humoral immunity by serological methods in animals vaccinated against orthopoxviruses often causes difficulties. This indicates that cellular immunity plays a more important role than humoral immunity in orthopoxviruses. This article presents the results of a study aimed at choosing the optimal dose of the virus to determine the neutralizing activity of the serum of animals vaccinated against orthopoxviruses in the neutralization test. According to the results of the study, the neutralization activity of the studied sera at high doses of the virus (ie 100 and 50 TCID50) did not exceed 2 log2, and at lower doses, the neutralization activity was from 4 to 6 log2. A dose of 25 TCID50 was selected as an effective dose among the tested doses of the virus to evaluate post-vaccination humoral immunity of cowpox-vaccinated animals using the neutralization test. This dose contributes to the detection of neutralizing antibody in the sample of the examined serum and its exact quantity, showing high sensitivity and specificity.