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Updated: May 16, 2026

Whole Blood Assay with Dual Co-Stimulation for Antigen-Specific Analysis of Host Immunity to Fungal and Viral Pathogens
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Whole Blood Assay with Dual Co-Stimulation for Antigen-Specific Analysis of Host Immunity to Fungal and Viral Pathogens

Published on: September 20, 2024

Memory CD4+ T cells are required for optimal NK cell effector functions against the opportunistic fungal pathogen

Michelle N Kelly1, Mingquan Zheng, Sanbao Ruan

  • 1Section of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA. mkelly3@lsuhsc.edu

Journal of Immunology (Baltimore, Md. : 1950)
|December 4, 2012
PubMed

Insights

Natural killer (NK) cells are crucial for controlling Pneumocystis pneumonia, an opportunistic infection. Their function is enhanced by CD4(+) T cells, highlighting a key immune interplay.

Area of Science:

  • Immunology
  • Infectious Diseases

Background:

  • The role of natural killer (NK) cells in opportunistic infections remains poorly understood.
  • Pneumocystis pneumonia (PCP) is a significant opportunistic infection, particularly in immunocompromised individuals.

Purpose of the Study:

  • To investigate the role of NK cells in host defense against Pneumocystis pneumonia.
  • To elucidate the interplay between NK cells and CD4(+) T cells during PCP.

Main Methods:

  • Murine model of Pneumocystis pneumonia.
  • CD4(+) T cell depletion and adoptive transfer experiments.
  • Flow cytometry to assess NK cell activation markers (NKp46, NKGD) and cytokine production (IFN-γ, granzyme B, perforin).

Main Results:

  • Loss of NK cells during immunosuppression led to increased Pneumocystis lung burden.
  • Fewer and less activated NK cells were observed in CD4(+) T cell-depleted mice during early infection.
  • Combined NK cells and CD4(+) T cells demonstrated enhanced fungal killing and perforin production compared to either cell type alone.
  • Memory CD4(+) T cells were essential for NK cell activation and effector function during Pneumocystis infection.

Conclusions:

  • NK cells play a vital role in controlling Pneumocystis pneumonia.
  • CD4(+) T cells enhance NK cell activation and effector functions, including cytokine and cytotoxic molecule production.
  • This study establishes a functional relationship between CD4(+) T cells and NK cells in the context of opportunistic fungal infections.

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