Human cellular immune response against Giardia lamblia 5 years after acute giardiasis

J Infect Dis. 2011 Dec 1;204(11):1779-86. doi: 10.1093/infdis/jir639. Epub 2011 Oct 11.


Background: Clinical and epidemiological studies have suggested the development of acquired immunity in individuals previously infected with Giardia lamblia. However, there are no data on the long-term cellular immunity and genotype cross-reactivity. An outbreak of assemblage B giardiasis in a nonendemic area made it possible to evaluate the long-term cellular mediated immunity and its specificity toward the 2 Giardia assemblages known to infect humans.

Methods: Peripheral blood mononuclear cells from 19 individuals infected with Giardia assemblage B 5 years previously and from 10 uninfected controls were cultured with antigens from assemblage A and B Giardia trophozoites for 6 days. Cell-mediated immunity was measured by a (3)H-thymidine proliferation assay and flow cytometric analysis of activation markers HLA-DR, CD45RO, CD25, and CD26 in T-cell subsets.

Results: Proliferation responses were significantly elevated in the group previously exposed to Giardia for nearly all Giardia antigens tested. Individual responses toward Giardia trophozoite whole cell, cytosolic, and excretory-secretory antigens from both assemblages correlated well. Activation marker responses were mainly seen in CD4 T cells.

Conclusions: G. lamblia infection induces long-term, albeit variable, cellular immune responses that are not assemblage specific and that are largely driven by CD4 T-cell activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, Protozoan / immunology*
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / metabolism
  • Cell Proliferation
  • Cells, Cultured
  • Dipeptidyl Peptidase 4 / metabolism
  • Female
  • Follow-Up Studies
  • Genotype
  • Giardia lamblia / genetics
  • Giardia lamblia / immunology*
  • Giardiasis / immunology*
  • HLA-DR Antigens / metabolism
  • Humans
  • Interleukin-2 Receptor alpha Subunit / metabolism
  • Leukocyte Common Antigens / metabolism
  • Lymphocyte Activation / immunology*
  • Male
  • Middle Aged
  • Norway


  • Antigens, Protozoan
  • HLA-DR Antigens
  • Interleukin-2 Receptor alpha Subunit
  • Leukocyte Common Antigens
  • Dipeptidyl Peptidase 4