Infectious Bronchitis Virus in the Chicken Harderian Gland and Lachrymal Fluid: Viral Load, Infectivity, Immune Cell Responses, and Effects of Viral Immunodeficiency

• Published in: Avian diseases 2008-12, Vol.52 (4), p.608-617
• Main Authors: van Ginkel, F. W, van Santen, V. L, Gulley, S. L, Toro, H
• Format: Article
• Language: English
• Subjects: animal glands; Animals; Antibodies, Viral; B lymphocytes; Birnaviridae Infections - transmission; Birnaviridae Infections - veterinary; Birnaviridae Infections - virology; cecal tonsil; Chicken anemia virus; Chickens; disease challenge; ELISPOT; Harderian gland; Harderian Gland - immunology; Harderian Gland - virology; immune response; Immunity, Cellular; Immunity, Mucosal; Immunocompromised Host; immunodeficiency; immunosuppression (physiological); Infections; infectious bronchitis; Infectious bronchitis virus; Infectious bursal disease virus; Infectious bursal disease virus - genetics; Infectious bursal disease virus - isolation & purification; Inoculation; lacrimal apparatus; Lymphocytes; microbial detection; mucosal immune responses; mucosal immunity; pathogenicity; Poultry Diseases - transmission; Poultry Diseases - virology; Research s; Reverse Transcriptase Polymerase Chain Reaction - veterinary; RNA; RNA, Viral - isolation & purification; specific pathogen-free animals; Specific Pathogen-Free Organisms; T lymphocytes; tears; Tears - virology; Trachea; trachea (vertebrates); Trachea - virology; Viral Load; Viruses
• ISSN: 0005-2086; 1938-4351
• DOI: 10.1637/8349-050908-Reg.1

We compared detection of infectious bronchitis virus (IBV) by quantitative RT-PCR (qRT-PCR) in tears and trachea of IBV-infected chickens and found that quantitative detection of IBV RNA in tears is more sensitive than in tracheal homogenates. Furthermore, we demonstrated that IBV contained in chicken lachrymal fluid is infectious and that tears of IBV-infected chickens can be used to infect naive chickens. We compared the immune responses to IBV in the Harderian gland and cecal tonsils of immunocompetent chickens and chickens infected with chicken anemia virus (CAV) and/or infectious bursal disease virus (IBDV). Flow cytometry analyses of lymphocytes in Harderian glands and cecal tonsils indicated that the relative abundance of IgM+ B cells in the Harderian glands and cecal tonsils following exposure to IBV in combination with immunosuppressive viruses was reduced compared to chickens infected with IBV alone. CAV, but not IBDV, reduced the CD4+/CD8+ T cell ratios compared to chickens infected with IBV alone. Enzyme-linked immuno-spot forming assays on cells in the Harderian glands and cecal tonsils of IBV-infected chickens indicated that maximum IBV-specific IgA-secreting cell responses were reduced in chickens infected with CAV. IBDV co-infected chickens displayed a delayed IgA response to IBV. Thus immunosuppressive viruses reduced B cells and T helper cells in the Harderian glands and cecal tonsils in response to IBV, and slowed the kinetics and/or reduced the magnitude of the mucosal immune response against IBV. We have shown for the first time that CAV affects pathogen-specific B cell responses in a mucosal effector site. Abbreviations: APHIS = Animal Plant & Health Inspection Service; CAV = chicken anemia virus; CT = cecal tonsil; CTL = cytotoxic T-lymphocyte; DPI = days post-IBV inoculation; EID50 = 50% embryo infective dose; ELISPOT = enzyme-linked immuno-spot forming; FACS = fluorescence-activated cell sorter; HG = Harderian gland; IBDV = infectious bursal disease virus; IBV = infectious bronchitis virus; Ig = immunoglobulin; PBS = phosphate buffer solution; PCR = polymerase chain reaction; qRT-PCR = quantitative RT-PCR; RT-PCR = reverse transcriptase PCR; SFC = spot-forming cells; SPF = specific-pathogen-free Virus de bronquitis infecciosa en el fluido lacrimal y en la glándula de Harder del pollo: Carga viral, infectividad, respuestas inmune celular y efectos del virus. Por medio de la prueba cuantitativa de la reacción en cadena por la polimer