Isolation of antibody to human placental alkaline phosphatase (PLAP) from extracts of human placentae.
OBJECTIVE
Human placental alkaline phosphatase (PLAP) is a unique placental antigen bound to the syncytiotrophoblast, which may be able to elicit a specific immune response in pregnancy.


METHODS
Antibody to PLAP was purified from placental extracts by: a) acid elution of membrane vesicles; b) purifying complexes of PLAP with human antibody on monoclonal antibodies to PLAP followed by denaturation of the enzyme; and c) by denaturation of PLAP in placental extracts and purification of antibody to PLAP on PLAP columns.


CONCLUSIONS
Specific antibody to PLAP is present in placental extracts, and is mostly bound to placental membrane preparations. PLAP is therefore immunogenic in pregnancy and could serve as a useful monitor of pregnancy-specific immunological responses. Since a similar enzyme appears in some cancers, it is possible that the immunization against PLAP in pregnancy will help to protect against the development of ovarian and endometrial cancer (the 'fetal antigen' hypothesis).
Freeman
J L
JL
Amplistar, Inc, Winston-Salem, NC 27101, USA.
Rhyne
P W
PW
Dean
D O
DO
Beard
G A
GA
Doellgast
G J
GJ
D000469:Alkaline Phosphatase; D000906:Antibodies / Q000302:isolation & purification*; D000911:Antibodies, Monoclonal / Q000276:immunology; D002846:Chromatography, Affinity / Q000379:methods; D005260:Female; D058851:GPI-Linked Proteins; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007074:Immunoglobulin G / Q000276:immunology / Q000302:isolation & purification; D007075:Immunoglobulin M / Q000302:isolation & purification; D007527:Isoenzymes / Q000187:drug effects / Q000276:immunology*; D010920:Placenta / Q000276:immunology*; D011233:Precipitin Tests / Q000379:methods; D011247:Pregnancy; D011489:Protein Denaturation; D012965:Sodium Chloride / Q000494:pharmacology; D014020:Tissue Extracts
D000906:Antibodies; D000911:Antibodies, Monoclonal; D058851:GPI-Linked Proteins; D007093:Imidazoles; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007527:Isoenzymes; D014020:Tissue Extracts; D012965:Sodium Chloride; C029899:imidazole; D000469:Alkaline Phosphatase; C019839:alkaline phosphatase, placental; D006851:Hydrochloric Acid