title: Alpha 2 macroglobulin is a maternally-derived immune factor in amphioxus embryos: New evidence for defense roles of maternal immune components in invertebrate chordate.
abstract: In fish, a series of maternal derived immune components have been identified in their eggs or embryos at very early stages, which are proposed to provide protections to themselves against pathogenic attacks from hostile environment. The phenomenon of maternal immunity has been also recorded in several invertebrate species, however, so far, very limited information about the maternal immune molecules are available. In this study, it was demonstrated maternal alpha2 macroglobulin (A2m) protein, an important innate immune factor, exists in the fertilized eggs of amphioxus Branchiostoma japonicum, an invertebrate chordate. Maternal mRNA of A2m was also detected in amphioxus embryos at very early developing stages. In addition, it was recorded that the egg lysate prepared from the newly fertilized eggs can inhibit the growth of both Gram-negative bacterium Escherichia coli and Gram-positive bacterium Staphylococcus aureus in a concentration dependent manner. The bacteriostatic activity can be reduced notably after precipitated A2m with anti-A2m antibody. Thus maternal A2m is partly attributed to the bacteriostatic activity. It was further demonstrated that recombinant A2m can bind to E. coli cells directly. All these points come to a result that A2m is a maternal immune factor existing in eggs of invertebrate chordate, which may be involved in defense their embryos against harmful microbes' attacks.
authors.affiliation: College of Marine Life Science and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Anjalika
authors.initials: A
authors.lastname: Pathirana
authors.affiliation: College of Marine Life Science and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Mingyue
authors.initials: M
authors.lastname: Diao
authors.affiliation: College of Marine Life Science and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Shibo
authors.initials: S
authors.lastname: Huang
authors.affiliation: College of Marine Life Science and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Zuo
authors.affiliation: College of Marine Life Science and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China. Electronic address: liangyujun@ouc.edu.cn.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Liang
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000276:immunology; D004926:Escherichia coli / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D007113:Immunity, Innate; D007155:Immunologic Factors / Q000235:genetics* / Q000378:metabolism; D064175:Lancelets / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D010063:Ovum / Q000276:immunology; D013211:Staphylococcus aureus / Q000502:physiology; D000511:alpha-Macroglobulins / Q000235:genetics* / Q000378:metabolism
chemical_list: D007155:Immunologic Factors; D000511:alpha-Macroglobulins
keywords: Amphioxus Branchiostoma japonicum; Bacteriostatic activity; Invertebrate; Maternal immunity; alpha2 macroglobulin