Pathological changes associated with Oesophagostomum columbianum infestations in sheep: Serum protein changes in relation to multiple infestation, intensity of infestation, and immunity

Abstract

A relationship between size of infesting dose and multiple infestation and the total serum proteins was demonstrated. During primary infestations with low and medium-sized doses of infective larvae, the total serum proteins fell. After infestation with large larval doses or after multiple infestations the total serum proteins increased.

Hypoalbuminaemia could be demonstrated after both primary and secondary infestations; also the animals given secondary infestation had failed to regain the level of serum albumin present before primary infestation.

Both α- and ß₁-globulins of sheep with either first or second infestation retained a level commensurate with, or decreased compared with, that in the control animals. These changes are discussed in relation to osmotic balance of the infected animal.

The ß₂-globulins increased during both primary and secondary infestations: however, the increase was greatest during the primary infestation. Increases in the y-globulin fraction also occurred but here the greatest increase occurred after secondary infestation. After primary infestation the y-globulin levels first fell and then increased as the infestation progressed.

There was a correlation between the complement fixation, but not the passive haemagglutination, antibody titres and the increased serum ß₂- and Y-globulin levels. However, the increased y-globulin levels after secondary infestation were too great to be solely accounted for by an immunological response.