Experimental inoculation of cats with human coronavirus 229E and subsequent challenge with feline infectious peritonitis virus.

Minimal-disease cats exposed to live human coronavirus 229E developed homologous antibody responses that suggested little or no replication of the virus in inoculated animals. Oronasal and subcutaneous inoculation of coronavirus 229E did not elicit an antibody response by heterologous (transmissible gastroenteritis virus, canine coronavirus) neutralization or by heterologous (transmissible gastroenteritis virus) kinetics-based enzyme-linked immunosorbent assay. No clinical signs attributable to coronavirus 229E were seen in inoculated cats. Although the number of animals in each of the five experimental groups was small (n = 2), antibodies produced in response to the virus did not appear to sensitize cats to subsequent feline infectious peritonitis virus challenge, but neither did they cross-protect cats against the challenge dose.