Prolactin synthesized and secreted by human peripheral blood mononuclear cells: an autocrine growth factor for lymphoproliferation.
Prolactin has been shown to have an immunoregulatory role in the rodent immune response. A prolactin-like molecule has also been found in mouse splenocytes and a human B-lymphoblastoid cell line. We have evaluated whether human peripheral blood mononuclear cells (PBMCs) synthesize and/or secrete prolactin. We used the polymerase chain reaction (PCR) to generate a 276-base-pair prolactin product from human PBMCs, and Southern blot analysis confirmed that it was related to prolactin. Western blotting using a polyclonal antibody to prolactin indicated that cell extracts prepared from human PBMCs contained a high molecular mass (60-kDa) immunoreactive prolactin. To determine whether this PBMC prolactin was being secreted, we developed a highly sensitive and specific hormonal enzyme-linked immunoplaque assay. With this assay, we were able to detect human prolactin secretion from concanavalin A (Con A)- or phytohemagglutinin-stimulated PBMCs but not from unstimulated PBMCs. We next sought to determine whether this secreted prolactin could function as an autocrine growth factor in lymphoproliferation. We observed that anti-human prolactin antiserum significantly inhibited human PBMC proliferation in response to Con A or phytohemagglutinin. We conclude that a prolactin-like molecule is synthesized and secreted by human PBMCs and that it functions in an autocrine manner as a growth factor for lymphoproliferation.
Sabharwal
P
P
Department of Medicine, Ohio State University Medical Center, Columbus 43210.
Glaser
R
R
Lafuse
W
W
Varma
S
S
Liu
Q
Q
Arkins
S
S
Kooijman
R
R
Kutz
L
L
Kelley
K W
KW
Malarkey
W B
WB
D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002460:Cell Line; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D004261:DNA Replication; D004797:Enzyme-Linked Immunosorbent Assay; D005091:Exons; D005260:Female; D006133:Growth Substances / Q000096:biosynthesis*; D006801:Humans; D007106:Immune Sera; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008214:Lymphocytes / Q000276:immunology; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010920:Placenta / Q000502:physiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D011388:Prolactin / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism
D006133:Growth Substances; D007106:Immune Sera; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011388:Prolactin; D004247:DNA