ABSTRACT
A mAb recognizing a 40- to 44-kDa monomeric molecule on the surface of chicken T cells was used to screen a cDNA expression library made from Con A-stimulated chicken spleen cells. The sequence of the cDNA obtained encoded a molecule having 50% amino acid sequence identity with mammalian CD28, but the cysteine residue involved in the inter-chain bridge of the mammalian CD28 homodimer was not conserved in the chicken sequence. The molecule produced in transfected COS-7 cells was also recognized by another mAb that had previously been thought to recognize an avian homologue of CD2. The sequence data establish that this molecule is a homologue of mammalian CD28 in the strict evolutionary sense.
Subject(s)
CD28 Antigens/classification , Chickens/immunology , T-Lymphocytes/immunology , Amino Acid Sequence , Animals , CD28 Antigens/metabolism , Cloning, Molecular , DNA, Complementary/genetics , Humans , Inbreeding , Mice , Molecular Sequence Data , Molecular Weight , Precipitin Tests , Sequence Alignment , Sequence Homology, Amino AcidABSTRACT
Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.
Subject(s)
Intestinal Mucosa/cytology , Lymphocytes/cytology , Animals , Cecum/cytology , Cecum/ultrastructure , Chickens , Epithelial Cells , Intestinal Mucosa/ultrastructure , Lymphocytes/ultrastructure , Microscopy, ElectronABSTRACT
Bursectomised chickens were protected against Marek's disease (MD) by vaccination with inactivated MD virus-specific antigens. The immunity was associated with lowered lymphocyte-associated MD viraemia following challenge. Evidence is presented that the immunity was not dependent on a humoral immune response but possibly on the presence of lymphocytes sensitised to virus-specific antigens.
ABSTRACT
Cyclophosphamide treatment of chicks abrogated the induction of immunity against Marek's disease (MD) by the herpesvirus of turkeys, but immunity eventually developed if a sufficient interval was allowed to elapse between vaccination and challenge. Vaccinated, cyclophosphamide-treated chicks showed severe suppression of antibody and immunoglobulin production even when immunity to MD was present, suggesting that resistance was not mediated by humoral immunity. Bursa and thymus weights of chicks were markedly reduced 7 days after treatment with cyclophosphamide, but at 35 and 70 days the mean weight of the thymus, but not of the bursa, was considerably restored. The results suggest that cyclophosphamide interferes with vaccinal immunity by an effect on the thymus and cell-mediated immunity, and not by an effect on the bursa and humoral immunity.
