Human CD4 restores normal T cell development and function in mice deficient in murine CD4

Area of Science:

• Immunology
• Molecular Biology
• Transgenic Animal Models

Background:

• The function of human coreceptors in murine models is crucial for understanding human immune responses.
• Mouse CD4-deficient (mCD4-/-) models lack essential T cell functions, limiting research.
• Investigating human CD4 (hCD4) functionality in mice is key for translational immunology.

Purpose of the Study:

• To determine if human CD4 (hCD4) can function physiologically in a mouse model.
• To assess hCD4's role in T cell development and selection.
• To evaluate hCD4's capacity to restore immune responses in mCD4-/- mice.

Main Methods:

• Generation of transgenic mice expressing hCD4 on an mCD4-/- background.
• Analysis of thymocyte development and T lymphocyte function.
• Examination of T cell receptor V beta family selection.
• Assessment of MHC class II-restricted T cell responses and humoral immunity.

Main Results:

• hCD4 demonstrated physiological activity from thymocyte development to mature T lymphocyte function.
• hCD4 participated in both positive and negative selection of T cells.
• Mature hCD4+ T cells were found in the periphery and restored deficient T cell responses.
• hCD4-reconstituted mice generated functional immunoglobulin G humoral responses.

Conclusions:

• Human CD4 is functionally active in mice, even in the absence of murine CD4.
• This transgenic model facilitates the study of hCD4 activity and HIV-1 gp120 pathogenesis.
• The findings support the use of hCD4 transgenic mice for immunological research.