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Biomedical subjects

A A Benedict

Publications and source records attributed to A A Benedict.

At least 19 recordsLinked to original sources
PubMed1994

Monoclonal antibodies with a high degree of specificity for Listeria monocytogenes serotype 4b.

Strains of Listeria monocytogenes serotype 4b account for a large fraction of sporadic listeriosis cases, as well as all major food-borne epidemics attributed to this pathogen. We have identified a set of three monoclonal antibodies which showed a high degree of specificity for strains of L. monocytogenes serotype 4b. Two of these antibodies (c74.33 and c74.180, isotypes immunoglobulin M [IgM] and IgG3, respectively) recognized all serotype 4b strains, whereas antibody c74.22 (isotype IgG1) failed to recognize certain epidemic-associated strains. The corresponding antigens were located on the surface of the bacteria and were expressed following bacterial growth in different media and over a wide range of temperatures (4, 22, and 37 degrees C). Heating L. monocytogenes cells at 80,90, or 100 degrees C abolished reactivity for c74.22 but not for c74.33 MAb. These MAbs were negative for all of the non-Listeria strains tested, including representatives of several gram-negative and gram-positive species. The surface antigen recognized by c74.22 appeared to be associated with the ability of the bacteria to enter (invade) mammalian cells in culture.

Animals↗
PubMed1990

Pathovar-Specific Antigens of Xanthomonas campestris pv. begoniae and X. campestris pv. pelargonii Detected with Monoclonal Antibodies.

Two monoclonal antibodies specific for lipopolysaccharide antigens of Xanthomonas campestris pv. begoniae and pv. pelargonii reacted with all of their respective pathovar strains and not with 130 strains of other xanthomonads or 89 nonxanthomonads tested. These results, as well as previous results, indicate that pathovar-specific monoclonal antibodies were readily generated to strains of X. campestris pathovars that generally infect single hosts.

Journal Article↗
PubMed1986

Tests of association of immunoglobulin allotype genes and viral oncogenesis in chickens.

Chickens from Regional Poultry Research Laboratory (RPRL) inbred line 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally-induced Rous sarcomas. In contrast, RPRL line 100 chickens are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than line 6(3). RPRL lines 100 and 6(3) differ for alleles at the IgG-1 (G-1) allotype locus, but have identical IgM-1 (M-1) allotype alleles. To test the possible association of the G-1 locus with variations in resistance to virally-induced tumors, homozygous and heterozygous genotypes among F3 crosses were infected. F3 chickens with different G-1 types were comparable in their resistance to MD tumors following inoculation with the JM strain of the MD virus, and for their ability to regress Rous sarcoma tumors induced by the Rous sarcoma virus (RSV) RAV-1. However, following RAV-1 virus infection a smaller proportion of G-1a/G-1aF3 or F4 birds developed LL tumors than G-1a/G-1e and G-1e/G-1e birds. Genes determining immunoglobulin heavy chains were therefore associated with a recessive resistance to B-cell lymphomagenesis in chickens.

Animals↗
PubMed1985

Inherited dysgammaglobulinemia of chickens: reduced incidence of disease in parabiotic chimeras.

University of California, Davis (UCD) line 140 chickens develop a dysgammaglobulinemia characterized as selective 7S immunoglobulin (Ig) deficiency with elevated serum IgM levels. To study the role of bursal development on the expression of dysgammaglobulinemia in these birds, we examined the effect of bursacyte transfer to line 140 birds and parabiosis between UCD 140 and a control line of chickens on changes in serum IgM and 7S Ig levels. Bursacyte transfer was performed by injecting 18-day UCD 140 embryos (which had been cyclophosphamide treated on Day 15) with bursacytes from major histocompatibility complex B-matched control line (11 X 58) F1 birds. This transfer produced little change in the incidence of dysgammaglobulinemia in UCD 140 transfer birds (56%) compared to unmanipulated line 140 birds (60%). These data reflect a failure of line 140, rather than technique, because successful reconstitution was seen using line 11 X 58 birds injected with 11 X 58 bursacytes. In contrast, the generation of UCD 140/line 11 X 58 chimeras significantly reduced the incidence of dysgammaglobulinemia in line UCD birds. Indeed, fusion of the chorioallantoic vascular system (parabiosis) of UCD 140 and 11 X 58 embryos on Day 15 decreased the frequency of dysgammaglobulinemia of UCD 140 parabionts to 14% compared to 66% in unmanipulated line 140 controls. The success of parabiosis was 83% as determined by demonstrating chimerism with allogeneic blood groups. Moreover, the frequency of dysgammaglobulinemia in the 17% of parabionts that did not reveal chimerism was similar to unmanipulated UCD 140 chickens.

Animals↗
PubMed1982

Inherited 7S immunoglobulin deficiency of chickens is associated with bursal degeneration anomalies.

Partially inbred line UCD 140 chickens develop an age dependent inherited 7S immunoglobulin deficiency with features similar to acquired human agammaglobulinemia. Serial and developmental observations in line UCD 140 and control lines 440 and 444 reveal a significant progressive premature involution of the bursa of Fabricius. These bursal changes are characterized by epithelial and medullary degeneration, reduced follicular bursacyte mitosis, and decreased follicular plasma cells. These abnormalities have not been previously described in other avian systems and suggest that this immune deficiency is due to a primary bursal disease.

Agammaglobulinemia↗
PubMed1981

The phylogenetic relationships of immunoglobulin allotypes and 7S immunoglobulin isotypes of chickens and other phasianoids (turkey, pheasant, quail).

Pheasants, quail and turkeys from different geographical locations were surveyed for the presence of eight 7S Ig and four IgM chicken allotypes. No IgM and only two 7S Ig allotypes were detected. Chicken 7S Ig allotypic specificity G-1.7 cross-reacted with pheasant and turkey isotypic specificities, and was absent in quail. The other determinant (G-1.9) cross-reacted with an allotype found only in turkeys and golden pheasants. These data suggest that G-1.7 and G-1.9 are probably phylogenetically ancient determinants and that polymorphism of chicken immunoglobulins arose after divergence of chickens from other phasianoid birds. Based on the allotypic and isotypic analysis of the 7S Ig antigenic determinants, turkey 7S Ig was as closely related to chicken 7S Ig as was pheasant 7S Ig. Jungle fowl, the ancestor of chickens, had most of the chicken 7S Ig and IgM allotypes present as polymorphic markers.

Animals↗
PubMed1980

Inherited 7S immunoglobulin deficiency in chickens: presence of suppressor T cells that suppress synthesis of 7S immunoglobulin but not IgM.

University of California (UCD) line 140 chickens, previously described to have an inherited 7S Ig deficiency and dysgammaglobulinemia associated with early bursal defects, and autoimmune phenomena were examined for the presence of suppressor cells. Pokeweed mitogen (PWM) stimulated UCD 140 peripheral blood lymphocytes (PBL) to synthesize IgM but not 7S Ig. In co-culture, UCD 140 PBL specifically inhibited 7S Ig but not IgM synthesis of PWM-stimulated PBL from normal birds. Normal 7S Ig synthesis usually was suppressed 40 to 80%, although PBL from some normal birds were not suppressible. Adoptive transfer of UCD 140 spleen cells to normal chicks resulted in early and transient decreased serum 7S Ig levels. Homology at the B locus (major histocompatibility complex) was not required for suppression. Higher levels of suppressor cells were found in UCD 140 than in normal birds as early as 13 days of age. The suppressor cells were found to be T cells as indicated by inactivation with anti-T antiserum but not with anti-B antiserum, and by suppression associated with T cell fractions obtained by nylon wool fractionation. UCD 140 B cells, obtained by nylon wool fractionation, were stimulated with PWM to synthesize 7S Ig when provided with normal T cells. These findings are discussed with particular reference to early bursal anomalies.

Agammaglobulinemia↗
PubMed1979

An allotypic marker on chicken immunoglobulin light chains.

The first chicken immunoglobulin light (L) chain allotypic specificity (L-1.1) to be described that was present on IgM, 7S Ig, Fab, and L chains was detected by radioimmunoassay. The gene controlling the expression of L-1.1 is inherited in a simple Mendelian fashion at an autosomal locus and is unlinked to a constant region heavy chain locus, four blood group loci and three loci determining lymphocyte cell surface alloantigens.

Animals↗
PubMed1978

Structural and genetic studies on chicken 7S immunoglobulin allotypes. IV. The presence of an unexpected chicken immunoglobulin heavy chain allotype: subclass or pseudoallele?

Low concentrations of allotypic specificity CS-1.1 were detected in the sera of two inbred chicken lines [University of California, Davis (UCD) 7 and Regional Poultry Research Laboratory 15I4] previously reported to lack this specificity. The CS-1.1 alloantigen in 15I4 chickens has the same specificity as the major allotype in a line of chickens (UCD 2) in which it was initially defined. In 15I4 chickens, CS-1.1 allotype is present on a population of molecules distinct from those which carry the major allotype; thus a second 7S Ig H chain locus, CS-2, is proposed. The concentration of CS-1.1-bearing molecules determined by two different methods was 7 microgram/ml and 230 microgram/ml in 15I4, whereas UCD 2 chickens had 4 mg/ml of CS-1.1 molecules. The levels of CS-1.1 inhibitory activity in 15I4 birds remained relatively constant over a 30-day period. The presence of two 7S Ig populations in 15I4 chickens may be interpreted as evidence either for 7S Ig subclasses with shared allotypes or for a pseudoallelic organization of genes controlling expression of 7S Ig H chains. The results were consistent with the presence of redundant C region genes, differing in allotypes, whose expression is under the control of an as yet undefined regulatory mechanism.

Alleles↗
PubMed1977

Genetic polymorphism of chicken 7S immunoglobulins.

A survey of 48 inbred lines derived from five sources in the United States and Europe revealed considerable genetic polymorphism of the CS-1 gene. A minimum of ten alleles were detected as unique combinations of CS-1 specificities. The relationship of some of the alleles would indicate that intracistronic recombination may have played a role in the production of some of the polymorphism.

Alleles↗