The immunoregulatory effects of merocyanine 540 on in vitro human T- and
B-lymphocyte functions
LG Lum, M Yamagami, BR Giddings, I Joshi, SL Schober, LL Sensenbrenner and F Sieber
Department of Medicine, Wayne State University, Detroit, MI.
Merocyanine 540 (MC 540) is a photoactive dye used to purge bone marrow of
tumor cells in autologous bone marrow transplantation. The effects of MC
540 on the lymphoid components in the marrow are unknown. This study
evaluates the treatment of lymphocytes by MC 540 (15 micrograms/mL) and
light (70 W/m2) on: (1) phytohemagglutinin and Con A- induced
proliferation; (2) allogeneic mixed lymphocyte cultures (MLC); (3) the
regulation of Ig synthesis by T cells; and (4) the ability of B cells to
produce polyclonal Igs as measured by an enzyme-linked immunosorbent
assay-plaque assay. The results show that MC 540 and light treatment
reduced Con A-stimulated T-cell proliferation greater than 50% after 30
minutes and greater than 80% after 60 minutes of MC 540-sensitized
photoirradiation. Ninety minutes of MC 540 and light exposure (designated
treatment) inhibited MLC greater than 90%. In polyclonal Ig synthesis,
T-cell helper activity could be abrogated by 90 minutes of treatment in
cocultures containing untreated B cells. Purified B cells treated for 90
minutes cocultured with normal T cells did not produce Ig. Treatment of B
cells completely inhibited Epstein- Barr virus-stimulated Ig synthesis.
These data show that T- and B-cell immunity is suppressed by the MC
540-sensitized photoirradiation. Treatment of bone marrow with MC 540 and
light may have profound effects on immune reconstitution in autologous
marrow graft recipients. More provocative is the fact that the same
immunomodulatory effects may be applicable to partially mismatched marrow
transplant situations as a means of reducing graft-versus-host reactions.
Volume 77,
Issue 12,
pp. 2701-2706,
06/15/1991
Copyright © 1991 by The American Society of Hematology
