Constantine H. Tempelis

The arthropod predators of ant-mimetic and aposematic prey: a serological analysis

Abstract. 1 ELISA (enzyme‐linked immunosorbant assay) was used to identify the arthropod predators of two common herbivores of a desert lupine: the aposematic plant bug Lopidea nigridea and the ant‐mimetic plant bug Coquillettia insignis. 2 Despite the fact that the prey are closely related, the two antisera were sufficiently specific to distinguish between the antigen against which they were formed and the antigen of the other species: both antisera were 3 times as reactive against their homologous antigen as they were against their heterologous antigen. 3 In tests on gut contents of field‐collected predators, ELISA results were generally consistent with laboratory no‐choice data for the five most common arthropod species on lupine: there was a strong correlation between attack rates for each predator‐prey pair as measured in the laboratory, and per cent positive reactions in ELISA as measured using field‐collected predators. In particular, L.nigridea antiserum was shown to be significantly less reactive against the crab spider Xysticus montanensis when compared to C.insignis antiserum, paralleling results of laboratory no‐choice experiments. 4 The usefulness of serological analysis as a tool for arthropod trophic link identification is discussed.

B cell activation in chickens induced by Staphylococcusaureus

Abstract Conventional mammalian polyclonal B cell activators were evaluated for activity in chicken spleen and peripheral blood lymphocyte (PBL) cultures. Although lipopolysaccharide was found to have a marginal influence on proliferation, two strains of the bacterium Staphylococcus aureus (Cowan I and Wood 46 strains) induced moderate proliferation in both spleen and PBL cultures. In spleen cell cultures the proliferating cell population was identified as the B cell. The mitogenic response required the presence of adherent cells since their removal eliminated the response. Evidence of in vitro polyclonal immunoglobulin synthesis could not be obtained. However, when administered intravenously, S. aureus induced polyclonal immunoglobulin synthesis.

Possible 110 kDa receptor for interleukin 2 in the chicken.

Chicken lymphoblasts were generated from spleen cells which had been incubated with concanavalin A (Con A) for 48 h. Monoclonal antibodies (mAbs) were produced by immunizing mice with 48-h Con A lymphoblasts. These antibodies were used to identify chicken lymphokine receptors on Con A-activated lymphocytes. The cellular enzyme immunoassay (EIA), with lymphoblasts and spleen cells as the target cells, was used to select for specific mAbs. One mAb was found by EIA to have a strong response against the lymphoblasts but weak against resting spleen cells. By immunofluorescence staining, it reacted strongly with lymphoblasts and weakly with resting spleen, erythrocytes, and bursal cells. This mAb was also shown to inhibit the lymphokine activity present in conditioned medium that was collected from 24-h cultures of Con A-activated spleen cells. By immunoprecipitation, this mAb precipitated a lymphoblast surface antigen with a molecular weight of about 110 kDa. This receptor may be analogous to the putative interleukin 2 gamma subunit recently described in human and mouse cell lines.

Characterization of a receptor on activated chicken T cells

Chicken lymphoblasts were generated from spleen cells which had been incubated with concanavalin A (Con A) for 48 h. Monoclonal antibodies were produced by immunizing mice with 48-h Con A lymphoblasts. The cellular ELISA, with lymphoblasts and spleen cells as the target cells, was used to select for specific monoclonal antibodies. A monoclonal antibody was found to have strong response against the lymphoblasts but not resting spleen cells. By immunofluorescence staining, this monoclonal antibody reacted strongly with lymphoblasts and did not react with resting spleen cells. This monoclonal antibody was also shown to inhibit the lymphokine activity present in conditioned medium (CM) which was collected from 24-h cultures of Con-A-activated spleen cells. In immunoprecipitation, this monoclonal antibody precipitated a lymphoblast surface antigen with a molecular weight of about 45 kDa.

Immunologic tolerance in the chicken. II. Isolation and characterization of a soluble factor from a macrophage-like cell from chickens tolerant to bovine serum albumin.

Abstract Macrophage-like cells harvested from 14-day-old chickens rendered tolerant at hatching with bovine serum albumin have been shown to release a soluble product which suppressed the adoptive secondary response to BSA. In addition, this suppressor factor suppressed the in vitro response to the non-cross-reacting antigen sheep red blood cells. The suppressor factor was found, by affinity chromatography, not to be composed of immunoglobulin but yet had the capacity to bind to the tolergen. Also, anti-line 3 antiserum, which is directed toward the major histocompatibility complex, removed the suppressive activity from macrophage supernatants.

The role of soluble protein a in chicken spleen cell activation

Soluble protein A (SpA) caused chicken spleen cell proliferation despite considerable evidence that SpA has no binding affinity for avian immunoglobulin (Ig). This biological activity was examined by several approaches. SpA-stimulated spleen cell cultures demonstrated no difference in proliferative responses regardless of the addition of human gamma globulin (HGG) or keyhole limpet hemocyanin. Adsorbents composed of HGG or hemoglobin were equally ineffective in abrogating the ability of SpA to induce spleen cell proliferation. In addition, ion exchange purified SpA was observed to induce comparable levels of spleen cell proliferation as ion exchange-affinity purified preparations. The lymphocyte subpopulation responsible for the observed proliferative response to SpA resides in the nylon wool adherent population. Nylon wool nonadherent lymphocytes failed to proliferate to SpA, but did proliferate in response to phytohemagglutinin as did nylon wool adherent cells. These data indicate that SpA is not responsible for the observed biological activity and suggest that components from Staphylococcus aureus other than SpA copurify during the preparation of SpA and are responsible for the activation of spleen cells.

Neonatal splenic suppressor cells in the chicken: I. In vivo suppression of the immune response to bovine serum albumin by normal and tolerized neonatal spleen cells

The presence of active splenic suppressor cells in neonatal chickens, either normal or tolerant to bovine serum albumin (BSA), was examined by assessment of their effect on both primary and adoptively transferred secondary responses to BSA or sheep red blood cells (SRC). Both normal and BSA tolerized spleen cells were shown to be highly suppressive of secondary anti-BSA responses generated by specifically primed adult spleen cells in inert recipients. Suppression of the secondary anti-BSA response by normal spleen cells was slightly less effective than that seen with BSA tolerant spleen cells. Transfer of BSA tolerant spleen cells into normal recipients, followed by BSA challenge, prevented any significant primary anti-BSA response. In contrast, transfer of normal spleen cells into normal recipients, followed by BSA challenge, failed to show any suppression of the resulting primary response. Neither normal nor BSA tolerant neonatal spleen cells were capable of suppressing either primary or secondary responses to SRC. Thus, chickens tolerized to BSA have suppressor cells specific for the tolerizing antigen. We present evidence that both the tolerance associated suppressors and the suppressors detected in normal neonatal chickens are T cells.

Partial characterization of chicken spleen cell culture supernatants stimulated with Staphylococcusaureus

The role of accessory cells in the proliferative response of chicken spleen cells to Staphylococcus aureus Cowan I (SAC) was examined. It was found that chicken spleen cells cultured with SAC produced a soluble molecule capable of causing proliferation when culture supernatants were added to spleen cells. The molecules responsible for this activity were stable in terms of exposure to extremes of heat and pH. Gel filtration of culture supernatants revealed biological activity, over a broad range of molecular weights, as measured by spleen cell proliferation. Similar findings were obtained when SAC was sonicated and evaluated following gel filtration. Exposure of culture supernatants to trypsin abrogated biological activity. The pivotal role of adherent cells in the generation of biologically active molecules is suggested by the ability of peritoneal exudate cells incubated with SAC to produce biologically active supernatants. In addition, the proliferative response of spleen cells to SAC was sensitive to chloroquine.

Immunological Tolerance in the Chicken

Two soluble non‐specific supprcssive factors were isolated by gel chromatography from the serum of chickens tolerant to bovine serum albumin (BSA). Fraction I was found by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) to contain five proteins with moi. wts from 200,000 to 900,000 unreduced and six proteins that ranged from 70,000 to 180,000 when reduced. The composition was primarily protein, with a small amount of carbohydrate and lipid. One component was identified as IgM, one as a lipoprotein. The others remain unidentified. No evidence of the tolerogen, BSA, was found. The second factor, fraction III of both (olerant and normal serum, was found by SDS‐PAGE to have two proteins with mol. wts of 54,000 and 78,000 in the unreduced form and contained a very small amount of protein, a large amount of carbohydrate, and no detectable lipid, Normal fraction III had two proteins with mol wts of 54,000 and 65,000 when reduced, whereas reduction did not affect tolerant fraction III. A soluble suppressive factor, secreted by cultured adherent cells of tolerant chickens, was found to be comparable to fraction III in molecular weight. Comparison of these results with those of other reported suppressive factors is made and possible identities of the suppressive components of fractions I and II are discussed.