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Biomedical subjects

L E Hanson

Publications and source records attributed to L E Hanson.

At least 37 records · Page 2Linked to original sources
PubMed1976

Evaluation of the immune response of cattle to leptospiral bacterins.

Cattle were vaccinated against leptospirosis with 3 bacterin preparations: (a) trivalent (serotypes grippotyphosa, pomona, and hardjo) whole cell bacterin; (b) bivalent pomona and hardjo whole cell bacterin; and (c) pentavalent (canicola, grippotyphosa, icterohaemorrhagiae, pomona, and hardjo) cell wall bacterin. Microscopic agglutinating antibody responses in cattle given the last-named bacterin were higher than those in cattle vaccinated with the 2 whole cell bacterins (trivalent and bivalent). However, microscopic agglutinating antibody responses occurred in all vaccinated cattle after they were given a challenge inoculation of serotype hardjo. Leptospires were isolated from 2 of 4 challenge controls (i.e., not given any bacterin), but none of the 15 vaccinated cattle given any one of the bacterins and then challenge inoculated with hardjo became culturally positive. It was concluded that the 3 multivalent bacterins were protective against experimental challenge inoculation of hardjo.

Animals↗
PubMed1976

Immunity to leptospirosis: renal changes in vaccinated cattle given challenge inoculum.

Resistance to renal leptospirosis was demonstrated in cattle vaccinated with Leptospira interrogans serotype pomona bacterin. Fewer vaccinated cattle given challenge inoculum of virulent serotype pomona leptospires 12 months after vaccination had kidneys with gross focal lesions in the cortex than did nonvaccinated controls. Histopathologic changes characteristically associated with renal leptospirosis occurred less frequently and renal tissue damage was less severe in vaccinated cattle than in nonvaccinated controls. The isolation of serotype pomona from only 1 of 29 vaccinated cattle, compared to 7 isolations from 11 nonvaccinated cattle, at 26 days after challenge inoculum was given, indicated that mild renal infection occurred only infrequently in vaccinated cattle. It appeared that challenge inoculation of vaccinated cattle with virulent serotype pomona leptospires stimulated an accelerated secondary immune response in which immunity limited the multiplication of leptospires in the kidney.

Animals↗
PubMed1976

Oral immunization of ducklings with attenuated duck hepatitis virus.

Duck hepatitis, a highly fatal disease of ducklings, must be controlled in successful commercial duck enterprises. Several procedures which have been effective in controlling the disease are 1) vaccination of adult breeders with passive transfer of antibodies through the yolk to the duckling, 2) administration of antisera to ducklings at the onset of signs of disease, and 3) parenteral vaccination of ducklings with attenuated DH virus after the loss of passive immunity. However, in each of these procedures, some losses usually occur and the administration of antiserum or vaccine to 2- to 3-week-old ducklings is costly and involves physical stress. Experimental studies of oral immunization in ducklings from immunized and nonimmunized parents were conducted to determine the feasibility of a convenient control program with little stress to the ducklings. Ducklings immunized with attenuated live duck hepatitis virus by intramuscular method, oral instillation, and through the drinking water were challenged with virulent duck hepatitis virus either intramuscularly or orally. Intramuscular, oral instillation, and drinking water application all provided adequate protection on challenge with virulent virus. Rise in neutralizing antibody was detected following immunization especially in sera of ducklings from nonimmunized parents. On the basis of successful experimental results, over 350,000 ducklings from immunized parents on a commercial farm have been sucessfully vaccinated by the drinking water method.

Administration, Intranasal↗
PubMed1975

Immunity to leptospirosis: Leptospira interrogans serotype pomona bacterins in cattle.

Immunity to renal leptospirosis was demonstrated in cattle vaccinated with Leptospira interrogans serotype pomona. Vaccinated cattle, challenge inoculated with virulent L interrogans serotype pomona organisms 12 months after vaccination, were resistant to renal infection; similarly inoculated, but nonvaccinated, cattle were susceptible to renal infection. Relationship was demonstrated between immunity induced in vaccinated cattle and that induced in hamsters vaccinated with a dilution of the same bacterin and later inoculated with virulent L interrogans serotype pomona organisms.

Agglutination Tests↗
PubMed1975

Immunoglobulins in cattle vaccinated with leptospiral bacterins.

The growth-inhibition test was used to detect specific antibodies against Leptospira interrogans serotype hardjo in isolated immunoglobulin (IgG and IgM) fractions of serums from cattle vaccinated with leptospiral bacterins. The growth-inhibiting antibodies were detected mainly in the IgG class. Agglutinated clumps also occurred with the IgM fraction. The serums collected from cattle 4 months after vaccination were negative in the microscopic agglutination test.

Animals↗
PubMed1975

Immunity to fowlpox.

Protection against fowlpox develops following vaccination or natural infection. The immune response can be measured for variable times either by challenging immunity of vaccinated birds for protection or by various serologic tests, e.g., viral neutralization, agar gel precipitation, complement fixation, passive hemagglutination, fluorescent antibody, and immunoperoxidase methods. Variation in the antibody response measured by these tests may be due to concentration of antibody present and sensitivity of the test employed. Available information suggests that both humoral and cellular immunity are involved in protection. There is a possibility of persistence of virus in latent infections which also might be responsible for protection.

Administration, Oral↗
PubMed1974

Immunoperoxidase staining of leptospires.

Leptospires were detectable by light microscopy when Formalin-fixed preparations were reacted by direct and indirect methods with horseradish peroxidase-labeled specific antibody.

Animals↗