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Biomedical subjects

D Rowley

Publications and source records attributed to D Rowley.

At least 91 records · Page 5Linked to original sources
PubMed1978

Changes in the immunoglobulin levels of the mouse gut and serum during conventionalisation and following administration of Salmonella typhimurium.

Increasess in all immunoglobulin classes, except IgM, were observed in the sera of specific pathogen-free (SPF) mice beginning 10 days after their removal from barrier conditions. Concentrations of serum immunoglobulins, comparable with those of conventional mice, were obtained in these animals between 21 and 35 days. Following the removal of germ-free mice from their sterile isolaters, their intestinal IgA levels increased over 35 days to attain levels found in conventional animals. A marked increase in serum immunoglobulin occurred within one day following intravenous administration of live Salmonella typhimurium organisms to SPF animals, and this persisted for longer than 7 weeks (the duration of the study), This rapid elevation in serum immunoglobulin was not elicited by nonbacterial antigens, killed Salmonellae, or viable Vibrio cholerae. Negligible amounts of this immunoglobulin increase could be attributed to specific antibody.

Animals↗
PubMed1978

Intestinal colonization and virulence of Salmonella in mice.

Within 3 h after oral challenge of mice with Salmonella typhimurium, foci of infection developed in the Peyer's patches of the small intestine. The numbers of organisms in the cecum, although in excess of those found in the small intestine, were not firmly associated with the cecal wall but were present largely in the cecum's contents. The Peyer's patches at first were remarkably incapable of eliminating even small numbers of Salmonella, but at about 7 days after infection developed the ability to eliminate a less virulent strain of S. typhimurium. Selected strains of Salmonella of varied virulence, and hybrid Escherichia coli/Salmonella typhimurium with varied O-antigens, revealed that those of low virulence could multiply within the intestinal Peyer's patches at nearly the same rate as a virulent strain, and the ability to multiply within the Peyer's patches was not dependent upon O-antigen type or smooth lipopolysaccharide. The ability of these strains to adhere to intestinal mucosa in vitro did not reflect on their ability to colonize the Peyer's patches, although strains of high in vitro adhesive ability appeared in greater numbers initially after oral challenge. Anti-O serum, ineffective in reducing the in vitro adhesive ability of virulent S. typhimurium, when given with the oral challenge prevented Peyer's patch colonization but was unable to prevent the appearance of a systemic infection. Anti-H serum, although effective in vitro in preventing adherence, had no effect in vivo. These experiments suggest that adhesiveness is neither essential nor sufficient for the virulence of Salmonella and that the usual development of a systemic infection after colonization of the small intestinal Peyer's patches may be subverted by the presence of O-antibody.

Antibodies, Bacterial↗
PubMed1977

Re-examination of small intestinal disposal of Vibrio cholerae in mice.

The rapid disposal of antibody-treated vibrios by peristalsis in whole animal models makes it difficult to obtain clear evidence for a simultaneous intra-intestinal bactericidal effect. In this paper we have re-examined the evidence for direct intra-intestinal killing. We have found that the data can be explained adequately by peristaltic effects without postulating a direct bactericidal action in vivo.

Animals↗
PubMed1976

Passive transfer of immunity to infection with Nematospiroides dubius from immunised mice to their offspring.

The results given below show that, whilst it is not possible to transfer immunity to infections with Nematospiroides dubius passively with serum from immune mice to normal adult mice, young born to immune females are resistant to this infection. The immunity is dependent on an intake of immunoglobulin via the milk for a period longer than 24 h. The passive transfer of immunity from immune mothers to neonatal mice does not appear to be dependent on a specific class of immunoglobulins.

Age Factors↗
PubMed1975

Further evidence for cross-linking as a protective factor in experimental cholera: properties of antibody fragments.

Enzymic fragments of IgG antibody were tested for their protective abilities in the infant mouse cholera model. F(ab')2 retained the full protective activity of the parent IgG molecule despite losses in complement fixation and opsonic functions. Fab' and Fab fragments also contained significant protective activity but at a level of only 10% of the intact IgG or F(ab')2. Self-recombinant univalent F(ab')2 also contained about 10% of the protective activity of the divalent F(ab')2 parent molecule. These results are interpreted as evidence that cross-linking is an important mechanism by which specific antibody protects mucosal surfaces against experimental infection with Vibrio cholerae.

Agglutination Tests↗
PubMed1975

Antibody cross-linking as a factor in immunity to cholera in infant mice.

Several antibody preparations were tested for their ability to reduce adsorption of Vibrio cholerae to isolated intestinal epithelial cells, and this ability was related to agglutination and protective activity in infant mice. The results demonstrate that (1) the reduction in adsorption of V. cholerae to epithelial cells correlates with the degree of agglutination for given antibody preparation; (2) intact tantibodies protect infant mice from cholera only at concentrations that agglutinate the bacteria; and (3) purified antibodies to flagellar antigens protect infant mice from cholera. These results indicate that cross-linking of bacteria by antibody causes a reduction in the number of organisms adsorbed to the intestinal wall. Thus antibody cross-linking plays an important role in immunity to cholera in infant mice.

Adsorption↗
PubMed1975

The effect of lysozyme on the complement-dependent bactericidal action of different antibody classes.

Preparations of rabbit, dog and sheep IgA, IgA and IgM were examined for their antibacterial effects using a complement-dependent bactericidal assay. IgM and IgG were efficient bactericidal antibodies in the presence of complement; IgA, however, contained negligible activity. Except for sheep IgG no enhancement of bactericidal activity was observed in the presence of added lysozyme.

Animals↗
PubMed1975

Dog immunoglobulins. II. The antibacterial properties of dog IgA, IgM and IgG antibodies to Vibrio cholerae.

Secretory IgA antibodies to Vibrio cholerae were purified from the parotid saliva and mammary secretions of locally and orally immunized dogs using gel filtration, ion-exchange chromatography and anti-immunoglobulin immuno-absorbents. IgM and IgG antibodies were isolated from serum by gel filtration and ion-exchange chromatography. IgA antibodies proved to have minimal, if any, activity in direct killing of bacteria in the presence of complement or in the promotion of phagocytosis. The minimal activity which IgA had in these assays could be accounted for by extremely small quantities of IgM antibody. The same IgA antibodies, mixed with the challenge innoculum of Vibrio cholerae and fed to infant mice, protected these mice as efficiently as IgG or IgM antibodies.

Animals↗
PubMed1975

Immunoglobulin synthesis and antibody content in the small intestine of the rabbit.

The concentration of immunoglobulin and specific antibody in the serum and the intestinal fluid and the rate of synthesis of immunoglobulin in the small intestine was measured in normal and immunized rabbits. IgA was found to be the predominant immunoglobulin in the intestinal fluid. IgA and IgG were secreted at rates of 4-3 mug/cm/hr and 1-3 mug/cm/hr respectively. Specific anti-Vibrio cholerae antibodies in the intestine were found mainly in the IgA class after oral immunization.

Animals↗
PubMed1975

Dog immunoglobulins. I. immunochemical characterization of dog serum, parotid saliva, colostrum, milk and small bowel fluid.

The levels of immunoglobulins A, M and G were measured in dog serum, colostrum, milk, parotid saliva and small bowel fluid using the single radial immunodiffusion method. All the external secretions except early colostrum, by contrast with serum, were found to be rich in IgA with small quantities of IgM and IgG. Exocrine immunoglobulins were partially characterized by gel filtration.

Absorption↗