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Parasitology Research

, Volume 85, Issue 4, pp 263–269 | Cite as

Changes in peripheral blood lymphocyte subpopulations and parasite-specific antibody responses in Trypanosoma evansi infection of sheep

  • Denis Nnabuike Onah
  • John Hopkins
  • Antony George Luckins
ORIGINAL PAPER

Abstract

This paper reports on changes in the lymphocyte composition of the peripheral blood in sheep infected with Trypanosoma evansi. In addition, parasite-specific IgG1 and IgM antibody responses were monitored using a double-sandwich enzyme-linked immunosorbent assay (ELISA) technique. Eight sheep were infected with 2 × 106T. evansi TREU 2143. The infection was characterised by chronicity and ended in self-cure in two of the sheep. These two sheep were designated group A, whereas the other six sheep, which remained parasitaemic until treated, were designated group B. Analysis of the peripheral blood lymphocytes (PBLs) by indirect immunofluorescence staining and flow cytometry revealed significant alterations in the numbers of T- and B-cell subsets detected in all infected sheep. In group A, whereas the numbers of CD8+ cells decreased, CD4+ cells showed marginal decreases, remaining at or above pre-infection figures and resulting in increase in the CD4:CD8 ratio. In group B, CD8+ cells showed few marginal decreases, being at or above pre-infection figures most of the time, whereas CD4+ cells decreased significantly from day 26 post infection (p.i.) such that the CD4:CD8 ratio decreased. Infection also resulted in significant increases (P < 0.001) as of day 26 p.i. in circulating B-cells in group B as shown by the numbers of sIg+, CD45R+, CD1+ and major histocompatibility complex (MHC) II+ cells. The increases, however, were moderate and biphasic in group A. T. evansi-specific IgM and IgG1 antibody isotypes were detected in all infected sheep, but their levels were significantly higher in group A than in group B (IgM P <0.05; IgG1P <0.01). In addition, although an initially higher level of IgM response was subsequently replaced by a higher level of IgG1 response in group A, this was never the case in group B until after drug treatment.

Keywords

Major Histocompatibility Complex Peripheral Blood Lymphocyte Trypanosoma Lymphocyte Subpopulation Antibody Isotype 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Denis Nnabuike Onah
    • 1
  • John Hopkins
    • 2
  • Antony George Luckins
    • 1
  1. 1.University of Edinburgh, Centre for Tropical Veterinary Medicine, Easter Bush, Roslin, Midlothian, EH25 9RG, Scotland, UKGB
  2. 2.University of Edinburgh, Department of Veterinary Pathology, Royal (Dick) School of Veterinary Studies, Summerhall, Edinburgh EH9 1QH, Scotland, UKGB

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