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Culling is often considered as a tool for controlling wildlife diseases that can also infect people or livestock. Culling European badgers Meles meles can cause both positive and negative effects on the incidence of bovine tuberculosis (TB) in cattle. One factor likely to influence the outcome of different badger-culling strategies for cattle TB is the reduction in badger population density achieved. However, this reduction is difficult to measure because badgers, being nocturnal and fossorial, are difficult to count. Here, we use indices of badger abundance to measure the population impacts of two culling strategies tested in Britain. The densities of badger setts and latrines recorded before culling were correlated with the densities of badgers captured on initial culls, suggesting that both were indices of actual badger abundance. Widespread ‘proactive’ culling was associated with a 73% reduction in the density of badger latrines, a 69% reduction in the density of active burrows and a 73% reduction in the density of road-killed badgers. This population reduction was achieved by a coordinated effort entailing widespread and repeated trapping over several years. However, this strategy caused only modest reductions in cattle TB incidence in culled areas and elevated incidence in neighbouring unculled areas. Localized ‘reactive’ culling caused a 26% reduction in latrine density, a 32% reduction in active burrow density and a 10% reduction in the density of road-killed badgers, but apparently increased the incidence of cattle TB. These results indicate that the relationship between badger population reduction and TB transmission to cattle is strongly non-linear, probably because culling prompts changes in badger behaviour that influence transmission rates. These findings raise serious questions about the capacity of badger culling to contribute to the control of cattle TB in Britain. [ABSTRACT FROM AUTHOR]

We have examined the morphology and functional characteristics of porcine intraepithelial lymphocytes (IEL). A subpopulation of IEL contains granules as seen in other species, and their ultrastructure was also similar. They were capable of producing T-cell growth factor and interferon on in vitro stimulation. IEL killed P815 cells in the presence of PHA, but did not kill K562 cells. [ABSTRACT FROM AUTHOR]

Intraepithelial lymphocytes (IEL) were isolated from the small intestine of pigs. They showed a strong blastogenic response to the T-cell mitogens phytohaemagglutinin A (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM); in contrast, mouse IEL responded weakly to these mitogens. The response of pig IEL was age-dependent, reaching adult levels by 9 weeks of age. Early weaning of pigs delayed the onset of this response. The effects of inflammatory mediators on the response of mouse IEL were also examined. [ABSTRACT FROM AUTHOR]

An enzyme-linked immunosorbent assay (ELISA) was adapted for the horse to investigate the production of antibody in response to subcutaneous, intrauterine or intravaginal immunization with dinitro-phenylated human serum albumin. An 1gM response was not detected, but antibodies of the IgGab, IgGc, IgGT and IgA isotypes were measured in serum, uterine and vaginal secretions. Local immunization produced antibody titres in serum and secretions, with evidence of significant local production. [ABSTRACT FROM AUTHOR]

The immunoglobulin content of porcine nasal, tracheal and bronchio-alveotar secretions was determined. IgA was the predominant immunoglobulin in nasal and tracheal secretions, there being no significant difference (P>0·1) between their IgA:IgG ratios of 2·7:1 and 2·4:1,respectively. In contrast, IgG was the predominant immunoglobulin in bronchioalveolar secretions, the IgA:IgG ratio being 0·7:1. The ability of tracheal and lung tissue to synthesize IgA and IgG was determined in vitro, Tracheal cultures synthesized more IgA than IgG whereas in the lungs the reverse occurred, the ratio of IgA: IgG synthesis being 1·4:1 and 0·4:1, respectively. The proportion of serum-derived IgA and IgG in respiratory tract secretions was determined by measuring the transfer of 125I - and 131I-labelled immunoglobulins from serum. It appeared that more than 97% of the IgA was produced locally. More significantly a proportion of the IgG was also synthesized locally. This proportion was smallest in nasal secretions (21·8%) and greatest in bronchio-alveolar secretions (62·6%). The results suggest that IgG, a large proportion of which is locally synthesized, is important in the homeostatic mechanisms of the lower respiratory tract. [ABSTRACT FROM AUTHOR]

The effect of feeding the B-cell mitogens Escherichia coli lipopolysaccharide and dextran sulphate on the development of orally induced tolerance to the contact sensitizing agent picryl chloride was studied in mice. Feeding either agent throughout the experiment or during tolerization, increased the tolerizing effect of a single feed of picryl chloride. [ABSTRACT FROM AUTHOR]

The secretory and systemic antibody responses to oral dead Escherichia coli were examined in A strain mice. The best responses were obtained in mice dosed with 1 x 1010 bacteria. Orally immunized animals showed an enhanced response to subsequent parenteral immunization with somatic antigens. This effect could be passively transferred with serum In contrast, the response to the capsular antigen K88 was reduced in the same animals. [ABSTRACT FROM AUTHOR]

The immune response of pigs to oral immunization with dinitrophenylated bovine gamma globulin (DNP-BGG) was assessed using the indirect macrophage migration assay. Two days' exposure to the antigen resulted in the inhibition of macrophage migration by supernatants of cultures from the intestine but not the mesenteric lymph node or spleen. Stimulation for 7 days resulted in macrophage inhibition by supernatants of lymphocyte cultures prepared from the intestine, mesenteric lymph node and spleen. Supernatants of splenic lymphocytes from animals stimulated for 2 or 3 days produced enhancement of macrophage migration. [ABSTRACT FROM AUTHOR]

Summary Mast cells in the equine respiratory mucosa were studied at both light - and transmission electron - microscope levels. Mast cells were identified at all levels of the tract, with the greatest cell density in the nasopharynx. The majority (57 to 94 per cent) of this cell population were located within the connective tissue of the lamina propria. Up to 20 per cent of these cells were associated with the mucosal glandular tissue, whilst small numbers were present within the surface epithelium and in association with nodular lymphoid tissue. In the peripheral lung tissue 20 per cent of the mast cell population was associated with the small airways, 25 per cent with the pleura, and 32 per cent with blood vessels. The fine and ultrastructural features of these mast cells resemble those described in other species, and their granules consist of two types which resemble human mast cells. [ABSTRACT FROM AUTHOR]

Oral immunization with 25 mg/day of ovalbumin resulted in a number of changes in non-specific immune responsiveness, including increases in antibody produced to T-dependent but not T-independent antigens and the abrogation of tolerance induced by both oral and intravenous routes. The effect was transient, sex- and strain-dependent. Evidence suggests that it is a consequence of cell-mediated immunity to the oral immunogen. [ABSTRACT FROM AUTHOR]

The introduction of 25 mg of a new protein antigen into the diets of mice produced transient increases in PVP clearance which reached a maximum 60 hr after the change of diet and had disappeared by 4 days. At the same time the immune responsiveness to unrelated antigens given parenterally was also raised transiently, reaching a peak 5 days following the change and disappearing by 7 days. In contrast the responsiveness to the fed antigen was diminished. [ABSTRACT FROM AUTHOR]

We report a girl with severe combined immunodeficiency with functional impairměnt of both humoral and cellular immunity despite normal numbers of B and T lymphocytes. Immunologic studies revealed hypergammaglobulinaemia, absent migratory response by polymorphonuclear leucocytes to chemoattractants, and diminished lymphocyte proliferative responses to mitogens, antigens and allogeneic leucocytes. However, stimulation of the patient's mononuclear leucocytes with the calcium ionophore, A23187, resulted in a normal proliferative response. We therefore postulate a membrane defect as the basis for immunologic dysfunction in this child. [ABSTRACT FROM AUTHOR]

We examined the effect of orally administered cholera toxin (CT) on the immune response to keyhole limpet haemocyanin (KLH) and ovalhumin (OVA) in high C57B1;6H2b) medium (CBAHM2k), and low (BALB/c H2d) responder I-A haplotypes to CF. Mice were fed OVA or KLH on three occasions at 10-day intervals and the effect of simultaneous feeding of CT determined, isotype-specific antibody levels were assayed in serum samples collected 7 days after the last immunization, Antibody was also measured in the supernatant of gut explant cultures incubated at either 4 or 37° C. Increased antibody levels in cultures kept at 37° C indicated release of local intracellular antibody Cholera toxin exerted an adjuvant effect on the mucosal response of all three strains to KLH and OVA. Overall, the responses to CT and the second protein were not correlated: we interpret these findings to indicate that while CT had an cited on the mucosal immune system which enhanets the immune response to itself and other protein antigens, the final outcome of the response to the second antigen is dependent on differences in the ability of the strains to process, recognize and respond to a particular antigen. [ABSTRACT FROM AUTHOR]

Oral immunization of the lactating sow with live Escherichia coli (O8:K88) stimulated an IgA anti-K88 antibody response in mammary secretions und significantly enhanced the capacity of whey to inhibit adhesion of the inoculum E. coli strain to isolated pig enterocytes. An increase in agglutinating unti-O8 activity was also evident in milk and was associated with both the IgA and IgM immunoglobulin classes. These results are consistent with the concept of a gut mammary link, although measurement of specific antibody in the intestinal secretions of these animals suggested that there may he a difference in response duration at the two secretory sites. Prolonged oral administration of heat-killed organisms also stimulated specific antibody synthesis within the mammary gland, although the response, particularly to the O antigen, was both reduced und delayed in its appearance. [ABSTRACT FROM AUTHOR]

The proportion of IgA, IgG and IgM in sow colostrums and milk that is derived from serum has been determined by measuring the transfer of 125I-labelled immunoglobulin from serum. All colostral IgG and a high proportion of IgM are derived from serum as is 40 per cent of IgA. Thus it would appear that colostrums is not a true secretion since 90 per cent of its immunoglobulin content is of serum origin. In milk, however, 90 per cent of IgA and IgM and 70 per cent of IgG would appear to be locally produced in mammary tissue. [ABSTRACT FROM AUTHOR]

Half-lives of immunoglobulins IgA, IgG and IgM labelled with Iodine-125 were measured and compared with the half-lives of these immunoglobulins calculated from plasma levels during the first 2–3 weeks of life. The two methods gave similar results for IgG and IgA, but the mean IgM half-life calculated from plasma IgM levels was significantly longer than the mean half-life of IgM-I125. IgM production and passage into the circulatory system during the first week of life could account for this difference. [ABSTRACT FROM AUTHOR]

Immunoglobulins IgG and IgA occur in adult sow urine as intact molecules, but not immunoglobulin IgM. Molecular fragments of all these types do however occur, although fragments of IgA are not as easily detectable as those of IgG. Urinary IgA was isolated and shown to exist primarily as a dimer. Antigenically and electrophoretically it is similar to the secretory IgA molecules of colostrum, milk, saliva and intestinal juice, and like those molecules possesses secretory component. Urine IgG is present as a 7S molecule and is similar to serum IgG. The IgG:IgA ratio of intact molecules in adult sow urine was 6:1; a similar ratio is found in colostrum. This compares with a 10:1 ratio occurring in serum. Thus there is relatively more IgA in urine than in serum compared to IgG, but relatively less than in milk. [ABSTRACT FROM AUTHOR]

Natural antibodies to the somatic antigens of Escherichia coli have been demonstrated in IgM, IgG and IgA porcine immunoglobulins. Antibody activity in all classes has been found in adult serum, milk whey and colostral whey and is transmitted from the latter fluid to the serum of post-suckling piglets. [ABSTRACT FROM AUTHOR]