Antigen-specific immune response of porcine T lymphocytes to various pathogens

Abstract

The importance of swine in agriculture has resulted in a substantial increase in research efforts on the swine immune system during the past few years. A better knowledge of the porcine immune system is required before improved vaccination strategies, the design of more efficient vaccines and breeding for disease resistance will be able to contribute to a reduction in the extensive economic losses caused by the disabling effects of viral, bacterial and parasitic infections. T lymphocytes play a central role in the antigen-specific immune response to the various pathogens. To detect and characterise porcine T lymphocytes, monoclonal antibodies (mAbs) were raised against different leucocyte differentiation antigens and classified for specificity in two international workshops. These mAbs have enabled detailed studies to be made on specific cell populations involved in the porcine immune response to pathogens, on T lymphocytes and on the peculiarities of porcine T lymphocyte sub-populations: extra-thymic CD4 + CD8 + Tlymphocytes and a substantial proportion of CD2"TCRyS + T cells. Furthermore, these reagents and the increased knowledge of the immune system have allowed studies of the interactions of T lymphocyte sub-populations with regard to different pathogens and the role which these play in infections.

Antigen‐specific proliferation of porcine CD8αα cells to an extracellular bacterial pathogen

“…CD8αα cells proliferating in response to B. hyodysenteriae antigen consisted of two populations based upon CD4 expression, CD4 – CD8 + and CD4 + CD8 + cells. Others have defined distinct characteristics for porcine CD4 + CD8 + cells in the recall response to viral antigens 11,32 , 33 . Porcine CD4 + CD8 + cells responding to an inactivated herpes virus vaccine consisted of a high percentage of large lymphoblasts and were thus characterized as proliferative based upon size and granularity.…”

“…Others have de®ned distinct characteristics for porcine CD4 + CD8 + cells in the recall response to viral antigens. 11,32,33 Porcine CD4 + CD8 + cells responding to an inactivated herpes virus vaccine consisted of a high percentage of large lymphoblasts and were thus characterized as proliferative based upon size and granularity. 10 We also determined that a majority of the CD4 + CD8 + cells proliferating in response to recall antigen were indeed large lymphoblasts.…”

Effect of therapeutic doses of enrofloxacin on circulating lymphocyte subpopulations in pigs

“…The significant reduction of CD4-CD8+ T-cell number indicates that enrofloxacin possesses the immunomodulatory effects, since this population of T-cells includes cells with spontaneous cytolytic activity against cancer cells and cytolytic T lymphocytes (CTLs) directed against cells infected with intracellular pathogens (14,15). CTLs are an important part of cell-mediated immunity against viral infections because they can directly attack host cells that have foreign antigen presented on the surface of MHC class I molecules (14).…”

Investigation of immune response and protection induced by a combined vaccination of modified live and killed porcine reproductive and respiratory syndrome virus vaccines and its potential use in a swine herd

“…According to the CD molecules, four major subpopulations of porcine lymphocytes have been described including CD4+CD8-, CD4-CD8+, CD4+CD8+, and CD4-CD8-T cells (Yang and Parkhouse, 1996;Saalmuller, 1998;Boeker et al, 1999;Terzic et al, 2002). …”

“…Porcine CD4-CD8+ T lymphocytes contain two main subsets of lymphocytes, which can be further characterized according to their immunological functions (Saalmuller, 1998). The first subset of this subpopulation has a spontaneous non-MHC-restricted cytolytic function and expresses low amounts of CD8 on the surface (Saalmuller et al, 1994).…”