Evaluation of the Replication, Pathogenicity, and Immunogenicity of Avian Paramyxovirus (APMV) Serotypes 2, 3, 4, 5, 7, and 9 in Rhesus Macaques

Khattar, Sunil K.; Nayak, Baibaswata; Kim, Shin-Hee; Xiao, Sa; Samal, Sweety; Paldurai, Anandan; Buchholz, Ursula J.; Collins, Peter L.; Samal, Siba K.

Neutralizing antibody titers in post-immunization sera collected on day 28 from rhesus macaques were measured in a microneutralization assay. Briefly, 2-fold serial dilutions of 100 ml of heat-inactivated monkey serum samples were mixed with 100 TCID 50 of the homologous APMV serotype and incubated at 37uC for 1 h. Following incubation, a 50 ml volume of the virusserum mixture from each serum dilution was added to approximately 150 ml of medium in quadruplicate wells of DF-1 (for APMV-2, -3, -4 and -9) or Vero (for APMV-5 and -7) cells in 96well plates. The plates were then incubated at 37uC for 72 h and were scored for virus replication based on HA activity of the supernatant. The titer was defined as the the mean reciprocal log 2 of the highest serum dilution resulting in complete neutralization of infection in 50% of the wells.