Infectious bovine keratoconjunctivitis II. Antibodies in lacrimal secretions of cattle naturally or experimentally infected with Moraxella bovis.

Preinfection, acute and convalescent phase lacrimal secretions from 20 cattle that had mild to severe keratoconjunctivitis (associated with natural or experimental Moraxella bovis infection) were tested for specific antibody to M. bovis as well as for immunoglobulins, particulary of the A class. The convalescent phase secretions from all four natural cases but from only seven of the 16 experimental cases contained increased amounts of immunoglobulins, predominantly of the A class. Only the secretions from cattle having severe keratoconjunctivitis contained precipitins specific for Moraxella bovis.Therefore, M. bovis specifically stimulates the appearance in tears of immunoglobulins that are important in the age associated, acquired resistance to reinfection with M. bovis.