Biomedical subjects

R H Jacobson

Publications and source records attributed to R H Jacobson.

86 records · Page 5Linked to original sources

PubMed1981

Enzyme-linked immunosorbent assay for measurement of antibody responses to Dirofilaria immitis in experimentally infected dogs.

The chronology of the antibody response to Dirofilaria immitis was measured in 2 groups of experimentally infected Beagle dogs. An enzyme-linked immunosorbent assay (ELISA), using a semipurified, adult D immitis-derived antigen was used to quantitate antibody levels. Group A consisted of 4 dogs inoculated once with D immitis infective larvae, 4 dogs inoculated twice with D immitis infective larvae, and 4 noninoculated dogs. Group B consisted of 26 dogs which were all infected with D immitis; however, 16 of these were given daily prophylactic concentrations of diethylcarbamazine (DEC) beginning 5 days before inoculation. Significant levels of antibody were demonstrable 16 weeks after inoculation of group A dogs and remained significantly increased throughout the study. There were no significant differences in antibody levels in dogs inoculated once or twice. Nontreated and diethylcarbamazine-treated dogs in group B developed significant antibody titers 11 weeks after inoculation. Significant differences in antibody titers between treated and nontreated dogs were first observed 13 weeks after inoculation; these differences remained for the duration of the investigation. There was no apparent correlation between antibody levels and either adult worm numbers or microfilaria counts.

Animals↗

PubMed1978

Immunization of mice with cobalt-60 irradiated Schistosoma mansoni cercariae.

Parameters of immunization of mice with 60Cobalt-irradiated Schistosoma mansoni cercariae are described and related to protection against subsequent challenge infection. Such immunization was found to be dependent on dose of irradiation, number of immunizing cercariae, and number and time course of infections. Low levels of resistance were obtained with low irradiation doses, in contrast to previous studies in mice. In general, resistance increased with increasing irradiation doses, up to approximately 48-56 Kr. Maximal resistance (70-80%) was induced by a single exposure to 250-500 cercariae, irradiated at a dose rate of 2 Kr/minute to a total dose of 56 Kr, administered percutaneously 4-6 wk prior to challenge. Challenge could be delayed for at least 15 wk after immunization without a decrease in resistance. The resistance obtained was not attributable to a delayed migration of challenge worms.

Animals↗

PubMed1977

The course of Hymenolepis nana infections in thymus-deficient mice.

The kinetics of infection with Hymenolepis nana was examined in normal thymus-deficient mice. Following inoculation with 5 cyticercoids, the number of adult lumen-dwelling H. nana in congenitally thymus-deficient (nude) mice ultimately was at least 75 times the maximum infection intensity of normal thymus-bearing mice or thymus-reconstituted nude mice. Similar results were obtained following inoculation of H. nana eggs into nude mice; although thymus-bearing mice eliminated their infections, nude mice harbored more than 1,000 adult worms throughout the 7 weeks of the experiments. These data show that in mice, immunity is not generated against H. nana in the absence of thymus function. The data also confirm and establish the requirement of cysticercoid development in the intestinal mucosa for stimulation of a protective immune response against H. nana.

Animals↗

PubMed1977

Studies on pronghorn antelope (Antilocapra americana) as reservoirs of anaplasmosis in Montana.

Twenty-six pronghorn antelope (Antilocapra americana) were collected in an area of eastern Montana where bovine anaplasmosis is enzootic. Their sera were examined for evidence of anaplasmosis by the complement-fixation test. Strong false positive reactions (3+ and 4+ reactors) occurred for 19 of the sera tested; 6 sera were anticomplementary. Inoculation of antelope blood into anaplasmosis, and anaplasma bodies were not found in stained blood smears of antelope or recipient calves.

Anaplasmosis↗

PubMed1977

Expulsion of Nippostrongylus brasiliensis from mice lacking antibody production potential.

Expulsion of the intestinal nematode of rodents, Nippostrongylus brasiliensis, was assessed in mice experiencing the immunosuppressive effects of anti-micron antibodies. Anti-micron treatment resulted in complete elimination of IgM and severe reduction of IgG1, IgG2 and IgA serum immunoglobulin levels. Specific antibody responses to sheep erythrocytes were virtually eliminated in anti-micron-treated mice as determined by direct and indirect plaque-forming-cell responses, haemagglutination and haemolytic assays. Using passive cutaneous anaphylaxis (PCA) and indirect haemagglutination (IHA) assays, antibodies against N. brasiliensis were not detectable in sera of anti-micron-treated mice; control mice, however, generated strong PCA and IHA responses. The kinetics of worm egg production coupled with adult worm recoveries at necropsy indicate that anti-micron treatment of mice had little or no effect on the capacity of mice to expel N. brasiliensis even though antibody production potential had been eliminated in these mice. Thus, anti-worm antibodies may not be requisite in the mechanism of N. brasiliensis expulsion from mice.

Animals↗

PubMed1976

The requirement of thymus competence for both humoral and cell-mediated steps in expulsion of Nippostorngylus brasiliensis from mice.

The worm damaging process (step 1 of Nippostrongylus brasiliensis expulsion from rodents) does not occur in congenitally thymus-deficient (nude) mice as determined by worm morphology, female worm fecundity, and kinetics of worm expulsion upon transfer into normal rats. Expulsion of damaged N. brasiliensis (step 2) does not occur subsequent to transfer of such worms from rats into nude mice. Morphological changes and reduced fecundity appeared in adult worms from normal thymus-bearing mice as early as the first day of patency (day 6 of infection). Thus, the worm damaging process is initiated several days earlier in mice than in rats and may, therefore, account for the reduced longevity of N. brasiliensis in mice compared with rats.

Animals↗

PubMed1975

Thymus dependence of tapeworm (Hymenolepis diminuta) elimination from mice.

Although normal mice eliminated the lumen-dwelling intestinal cestode Hymenolepis diminuta by day 21 post-cysticercoid inoculation, congenitally thymus-deficient (nude) mice maintained their work burdens. Nude mice grafted with thymus glands or injected with thymus cells eliminated their worms.

Animals↗

PubMed1974