Natural Killer Cells and Mast Cells from gp49B Null Mutant Mice Are Functional

Abstract

Immune responses are controlled by a combination of positive and negative cellular signals. Effector cells in the immune system express inhibitory receptors that serve to limit effector cell expansion and to protect the host from autoreactivity. gp49B is a receptor of unknown function that is expressed on activated mast cells and natural killer (NK) cells and whose cytoplasmic tail endows it with inhibitory potential. To gain insight into the function of gp49B in mice, we disrupted the gp49B gene by homologous recombination. gp49B⁰ mice were born at expected ratios, were healthy and fertile, and displayed normal long-term survival rates. gp49B⁰ mice showed no defect in NK or mast cell development. Furthermore, NK and mast cells from the gp49B⁰mice showed activation properties in vitro similar to those of cells isolated from wild-type mice. Therefore, gp49B is not critical for the development, expansion, and maturation of mast cells and NK cells in vivo. The healthy status of gp49B⁰ mice makes them suitable for testing the role of gp49B in immune responses to infectious agents.

ACKNOWLEDGMENTS

S. Rojo and C. Stebbins contributed equally to this work.

Generation of gene-targeted ES cells and production of chimeric mice were performed by Ren-ju Hu in the laboratory of Hua Gu (Laboratory of Immunology, NIAID, NIH).