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Human megakaryocytes have a CD4 molecule capable of binding human immunodeficiency virus-1
Y H Kouri1, W Borkowsky, M Nardi
1Department of Medicine, New York University Medical Center, New York 10016.
Abstract:
Most human megakaryocytes (MGKs) express the CD4 antigen on their surface. Approximately 25% have a CD4 receptor density comparable to that of CD4+ T cells (Basch et al, Proc Natl Acad Sci USA 87:8085, 1990). In these studies, we show: (1) the presence of mRNA for CD4 in human MGKs; (2) the binding of human immunodeficiency virus-1 (HIV-1) to human MGKs; (3) the inhibition of binding by anti-CD4 (Leu3a) antibody or rCD4; (4) the infection of a human MGK line, CHRF-288 with HIV-1; and (5) inhibition of infection with anti-CD4. Human MGKs have mRNA for CD4 as shown by in situ hybridization with an RNA probe synthesized from a 3-kb cDNA sequence of plasmid pSP65.T4.8 containing the full-length CD4 sequence. MGKs (23% +/- 17%) bound HIV-1, as determined by anti-gp120 and anti-CD41 staining. Binding to human MGKs could be inhibited 55% to 75% with anti-CD4 or rCD4, respectively. Infection of a CD4+ MGK line (CHRF-288) could be accomplished with HIV-1, as determined by proviral DNA polymerase chain reaction and p24 production. Preincubation with anti-CD4 inhibited apparent proviral DNA infection by 100% and p24 production by 65% to 70%. Thus, human MGKs have a CD4 receptor capable of binding HIV-1. Using this receptor, HIV-1 can infect cells representative of the MGK lineage.
Insights
Human megakaryocytes (MGKs) possess CD4 receptors that bind to human immunodeficiency virus-1 (HIV-1). This interaction facilitates HIV-1 infection in MGK lineage cells, highlighting a potential pathway for viral replication.
Area of Science:
- Immunology
- Virology
- Hematology
Background:
- Most human megakaryocytes (MGKs) express the CD4 antigen.
- A subset of MGKs exhibits CD4 receptor density similar to CD4+ T cells.
Purpose of the Study:
- To investigate the presence of CD4 mRNA in human MGKs.
- To determine if human immunodeficiency virus-1 (HIV-1) binds to and infects human MGKs.
- To assess the role of the CD4 receptor in HIV-1 binding and infection of MGKs.
Main Methods:
- In situ hybridization to detect CD4 mRNA in MGKs.
- Flow cytometry using anti-gp120 and anti-CD41 antibodies to assess HIV-1 binding.
- Infection assays with HIV-1 on a human MGK cell line (CHRF-288).
- Inhibition studies using anti-CD4 antibody (Leu3a) and recombinant CD4 (rCD4).
- Polymerase chain reaction (PCR) for proviral DNA and p24 antigen detection to confirm infection.
Main Results:
- CD4 mRNA was detected in human MGKs.
- Human MGKs demonstrated binding of HIV-1, with inhibition observed using anti-CD4 or rCD4.
- The human MGK cell line CHRF-288 was successfully infected with HIV-1.
- Anti-CD4 antibody significantly inhibited HIV-1 infection (proviral DNA and p24 production) in CHRF-288 cells.
Conclusions:
- Human MGKs express functional CD4 receptors capable of binding HIV-1.
- HIV-1 can infect cells of the megakaryocyte lineage via the CD4 receptor.
- These findings suggest a potential role for MGKs in HIV-1 pathogenesis.