Protection conferred on a host by inoculation with one strain or component of a microorganism that prevents infection when later challenged with a similar strain. Most commonly the microorganism is a virus.
A species of CORONAVIRUS causing pneumonia in newborn rats but a clinically inapparent infection in adults. It is separate but antigenically related to MURINE HEPATITIS VIRUS.
Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.
Immunoglobulins produced in response to VIRAL ANTIGENS.