Increase of T-cell receptor gamma/delta-bearing T cells in cord blood of newborn babies obtained by in vitro stimulation with mycobacterial cord factor.
Cord blood T lymphocytes proliferated in vitro in response to mycobacterial organisms but did not proliferate in the presence of tuberculin purified protein derivative. Components recognized by cord blood T cells were resistant to protease digestion. In contrast, T lymphocytes derived from tuberculin-positive adult peripheral blood proliferated when stimulated by the protease-sensitive component of mycobacterial organisms or purified protein derivative, confirming that adult T cells respond to protein components whereas cord blood T cells respond to the nonpeptide component of mycobacteria. In vitro culture of cord blood lymphocytes stimulated by either mycobacterial lysates or the lipid fraction showed increases in the numbers of T-cell receptor (TcR) gamma/delta T lymphocytes with no changes in the numbers of TcR alpha/beta T lymphocytes in contrast to the in vitro cultures of adult blood lymphocytes stimulated with mycobacterial ligands in which no increase of TcR gamma/delta cells was observed. Interleukin-2 receptor (CD25) and Ia antigen (HLA-DR) analyses evidenced the activation of a large proportion of cord blood gamma/delta T cells which had increased after stimulation with mycobacteria in vitro. Further characterization of mycobacterial ligand suggested that the lipid fraction of mycobacterial lysate or trehalose dimycolate-cord factor was the most plausible cause for T-cell proliferation in cord blood. These results suggest that when the gamma/delta T cells in a newborn infant not yet sensitized to any pathogenic organisms are confronted by a mycobacterium, they respond nonspecifically to the mycobacterial organism or its lipid component (cord factor). gamma/delta T cells may therefore play a distinct role in forming the first line of the host defense system against certain microorganisms.
Tsuyuguchi
I
I
Osaka Prefectural Habikino Hospital, Japan.
Kawasumi
H
H
Ueta
C
C
Yano
I
I
Kishimoto
S
S
D003311:Cord Factors / Q000276:immunology*; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D007231:Infant, Newborn; D008024:Ligands; D008055:Lipids / Q000494:pharmacology; D008213:Lymphocyte Activation; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011247:Pregnancy; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*
D003311:Cord Factors; D000949:Histocompatibility Antigens Class II; D008024:Ligands; D008055:Lipids; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015375:Receptors, Interleukin-2