FeLV p27 antigenemia ELISA data. FeLV p27 antigenemia ELISA data. FeLV p27 antigen ELISA to detect persistent antigenemia in the three groups (group A, Nobivac feline 2-FeLV; group B, PureVax recombinant FeLV; group C, control group). Optical densities (OD) ≥ 0.200 were considered positive for the FeLV p27 antigen. Statistically significant differences were seen between the Nobivac feline 2-FeLV and control groups at all time points (P < 0.03). Statistically significant differences were seen between the Nobivac feline 2-FeLV and PureVax recombinant FeLV groups at weeks 3, 4, 6 to 9, and 11 postchallenge (*, P < 0.01). No statistically significant differences were seen between the PureVax recombinant FeLV and control groups at any time points (P > 0.08). M. Patel et al. Clin. Vaccine Immunol. 2015; doi:10.1128/CVI.00034-15