Record Details
The immunological response of sheep to irradiated and non-irradiated infectious larvae of Haemonchus contortus (Rudolphi 1803) Cobb, 1898
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The immunological response of sheep to irradiated and non-irradiated infectious larvae of Haemonchus contortus (Rudolphi 1803) Cobb, 1898 |
| Names |
Stevens, James Orval
(creator) Pilcher, K. Stephen (advisor) |
| Date Issued | 1967-05-11 (iso8601) |
| Note | Graduation date: 1967 |
| Abstract | Ten helminth-free sheep were given two doses of 10,000, X-irradiated, H. contortus, third stage larvae 30 days apart. These animals and a group of ten non-vaccinated sheep were challenged with 50,000, normal, H. contortus, third stage larvae 60 days following the second vaccination. Antibody levels were measured in both groups by the Indirect Hemagglutination Test (IHA) with ground larval antigen. Significant levels of antibodies were not found in vaccinated animals following administration of either dose of vaccine. Following challenge, the vaccinated group contained antibodies of significant high levels as compared to the control group. The highest antibody titers were found in vaccinated animals which did not develop a protective immunity of a level high enough to resist challenge; and resistance in the individual vaccinated animals was not related to the individual antibody levels. Antigens extracted from H. contortus third stage larvae, ground with a Potter-Elvehjem grinder, were satisfactory for the IHA test. Tanned red blood cells did not have a limited adsorption capacity for ground larval antigen. Larvae ground in normal saline were found to yield the most sensitive ground antigens. Dextrose-Gelatin-Veronal-Buffer was found to be a satisfactory replacement in the IHA test for veronal buffer with serum. Saline extracts from metabolizing, early fourth stage, H. contortus larvae were satisfactory as antigens in the IHA test. Antigen of extremely high sensitivity was extracted from third stage larvae in the process of exsheathment. When tested against selected positive H. contortus antisera, this exsheathment antigen was seven times more sensitive than the routine ground larval antigen. Immunoelectrophoresis (IE), with rabbit antisheep globulin as antibody, was used successfully to determine qualitative changes in specific fractions of serum samples taken from vaccinated and non-vaccinated sheep. An unidentified fraction, seen as a precipitation arc in the slow beta or fast gamma region, appeared in all reactions of serum samples taken from sheep exposed to H. contortus larvae. Increases in alpha₂-II, alpha₂-III, alpha₂-IV, beta₂-I and beta₂-III globulin fractions, as evidenced by increases in densities of precipitation arcs representing these fractions in reacted serum samples, were, in general, associated only with successfully immunized sheep. Of these fractions, beta₂-III globulin increases were found to be most closely associated with successfully immunized animals. Increases in alpha₁ globulins were seen to be limited to heavily infected, non-immune animals. No apparent changes in gamma globulins were observed in IE reactions of any serum sample. Increases and decreases in densities of the beta₁-I globulin fraction were directly correlated with the anemic status of the animal and the arc representing this fraction was absent or very light in reactions from animals with severe anemia. When H. contortus antisera were subjected to electrophoresis and subsequently reacted against ground H. contortus larval antigen placed in the antigen trough, a precipitation arc, apparently indicating antibody against H. contortus, developed in the alpha globulin region. This fraction was easily washed out during processing and could not be stained with Amido Black 10B. It could not be identified. Immuno-diffusion studies of serum samples from vaccinated and non-vaccinated sheep, when tested against ground H. contortus larval antigen, were inconclusive. Multiple precipitation arcs which developed between antigen and serum wells were, in general, associated only with serum samples taken from sheep successfully immunized against H. contortus. |
| Genre | Thesis/Dissertation |
| Topic | Sheep -- Diseases |
| Identifier | http://hdl.handle.net/1957/47292 |
