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.

To evaluate the replication of APMVs in the lower respiratory tract of the inoculated animals, BALs were collected on days 2, 4, 6 and 8, and tracheal lavages were collected on days 10 and 12. All samples were processed and titrated as described above. Virus was detected only in the BAL samples (Table 3) . Each strain except for wt APMV-5 replicated detectably in the lower respiratory tract of rhesus macaques. Specifically, wt APMV-2 was detected in all 4 animals on day 2, and in 1 or 2 animals on days 4 and 6, respectively ( Table 3) . Replication of rAPMV-2 (type 1 Africa) seemed to be more robust: virus shedding was detected from day 2 to day 6 in all of the animals, with mean daily titers ranging from 1.5 to 2.5 log 10 EID 50 per mL. Shedding of wt APMV-3 was detected in all inoculated animals until day 4, and in 2 animals until day 6, with mean daily titers of 0.9 to 2.2. Interestingly, while wt rAPMV-4 had not been detected in nasal washes from any animal, as described above (Table 2) , this virus was detected on day 2 in BALs of 2 animals (Table 3) . Similarly, the F cleavage mutant rAPMV-4/Fc-BC had not been detected in nasal wash specimens (Table 2) , it was detected on days 2 and/or 4 in BALs of 3 of 4 inoculated animals. Whereas wt rAPMV-2 was detected in BALs only on day 2, the cleavage site mutant derivative was detected on days 2 and 4. Consistent shedding of wt APMV-7 and rAPMV-7/Fcs-5B was detected in all of the animals from days 2 to 6. Mean daily titers for the 2 viruses were similar and ranged from 1.2 to 3 log 10 EID 50 per mL. Thus, while it appeared that the cleavage site mutation Fcs-5B had a negative effect on replication wt APMV-2 of APMV7 in the upper respiratory tract (Table 2) , it did not affect replication of APMV-7 in the lower respiratory tract (Table 3) . Both versions of APMV-7 were detected more readily from the lower versus the upper respiratory tract. Wt APMV-9 was detected on day 2 in 3 of the 4 inoculated animals, and in 1 animal each on day 4 and 6.