Activation of a Macrophage by a Th1 Lymphocyte

Fig. 1: Activation of a Macrophage by a T_H1 Lymphocyte

1. Engulfed bacteria inside a phagosome or a phagolysosome.
2. An activated T_H1 lymphocyte binds to a peptide/MHC-II complex on a macrophage by way of its TCR and CD4 molecule. Co-stimulatory molecules such as CD40L on the T_H1 cell then bind to CD40 on a macrophage.
3. This triggers the T_H1 lymphocyte to secrete the cytokine interferon-gamma (IFN-γ) that binds to IFN-γ receptors receptors on the macrophage.
4. The IFN-γ activates the macrophage enabling it to produce more hydrolytic lysosomal enzymes, nitric oxide, and toxic oxygen radicals that destroy the microorganisms within the phagosomes and phagolysosomes.

Illustration of Activation of a Macrophage by a TH1 Lymphocyte .jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.

Last updated: Feb., 2021
Please send comments and inquiries to Dr. Gary Kaiser

Fig. 1: Activation of a Macrophage by a TH1 Lymphocyte

Fig. 1: Activation of a Macrophage by a T_H1 Lymphocyte