Functional characteristics of cord blood T lymphocytes after lectin and anti-CD3 stimulation

Abstract

Newborns are more susceptible than adults to infections, which suggests a relative immaturity of the immune system early after birth. Cord blood T cells differ significantly both in surface phenotype and function from adult T cells. We examined the proliferation and expression of activation molecules by lymphocytes isolated from umbilical cord blood or peripheral blood of adults. The lymphocytes were cultured for 5 days in the presence of phytohemagglutinin, concanavalin A, or anti-CD3 monoclonal antibody. Cord blood T cells expressed the CD45RA molecule, while a low proportion expressed the RO isoform, a marker of primed or activated lymphocytes. Furthermore, more than 95% of neonatal lymphocytes bear the CD38 molecule, but do not express the CD57 molecule. After stimulation by phytohemagglutinin or concanavalin A, the lymphocytes from newborns were activated and proliferated as efficiently as adult T cells. Anti-CD3 did not cause neonatal lymphocytes to proliferate, but these cells expressed activation molecules, such as HLA-DR antigens and the receptor for interleukin-2 and transferrin. The relevance of these findings to tolerance induction in immature cord blood T cells is discussed.

Analysis of Monocyte Chemotactic Protein-1 Production in Different Major Histocompatability Complex-Restricted Antigen Presentation Systems

“…Thus, it appears that Con A-induced T cell proliferation proceeds via a route different from that of MHC II-antigen binding and probably without the need for close cellto-cell contact. In this system, mainly the T cell is activated, and not the antigen-presenting cell (19,20). In contrast to aspecific receptor cross-linking on the lymphocyte by Con A, it appears that highly specific Engagement of the MHC II-antigen complex by its specific TCR and probably the engagement of costimulatory adhesion molecules delivers activation signals into both the T cells and the APCs (17).…”

“…The route via which Con A induces T cell proliferation is not known in detail. Commonly, Con A has been viewed as an APCindependent stimulus, directly cross-linking receptors on the lymphocyte (17,19). There is, however, evidence that Con A-induced T cell proliferation is greatly enhanced in the presence of APCs and is completely abolished when T cells are the only cells present in the culture [(20) and Fig.…”

Early Immune Reaction after Reduced-Intensity Cord-Blood Transplantation for Adult Patients

“…Another advantage of cord blood is immaturity of immune function. Long-lasting unresponsiveness and lack of proliferation of cord-blood lymphocytes on rechallenge with alloantigen might lead to reduced incidence of graft-versus-host disease (GvHD) after CBT (2), whereas a graft-versus-leukemia (GvL) effect might be maintained owing to the presence of precursor T and natural killer cells (3,4). The feasibility of related and unrelated CBT has been demonstrated for pediatric patients (5)(6)(7)(8), and the technique has been successfully applied to adults (9 -12).…”

Tumour necrosis factor‐α‐induced apoptosis in cord blood T lymphocytes: involvement of both tumour necrosis factor receptor types 1 and 2

“…Distinct immunological properties of neonatal T cells are likely to have consequences in the outcome of cord blood transplants. Cord blood T cells express the naõ Ève lymphocyte marker, CD45RA; only a small proportion of these express the CD45RO isoform, a marker of primed or activated lymphocytes (Lucivero et al, 1996). After stimulation by mitogens, the newborn naõ Ève T cells are activated and proliferate as efficiently as adult T cells, but do not produce IL-2, IL-4 or INF-g.…”