title: Horse IgG- and ostrich IgY-F(ab')₂ groups have different affinities for mice erythrocytes and lymphocytes. Implications for avian immunoglobulin therapeutic usefulness.
abstract: We used high sensitivity and resolution fluorescence microscopy to study the interaction of ostrich IgY, horse F(ab')₂ and horse IgG with mice lymphocyte and erythrocyte plasma membrane. The immunoglobulins were labeled with fluorescein isotiocyanate (FITC). Our results show an interaction of IgY with lymphocyte plasma membrane which does not result in endocytosis of the labeled protein. Less IgG and its F(ab')₂ fraction bind to lymphocytes, and this binding seems to be followed by endocytosis producing a diffuse cytoplasmic fluorescence in most lymphocytes exposed to FITC-IgG or FITC-F(ab')₂. Cytoplasmic fluorescence resembling FITC was not observed in lymphocytes exposed to FITC-IgY. Receptors in the erythrocyte membrane also differentiate between avian and horse Ig; while erythrocytes exposed to horse Igs became intensely fluorescent for at least 5 h, no erythrocyte labeling occurred when FITC-IgY was used. Our results suggest that IgY may be a stronger activator of adaptive immunity than horse IgG in mammals. Adaptive immunity against IgY is detrimental to its IV therapeutic use in humans and other mammals.
authors.affiliation: Laboratory on Cellular Neuropharmacology, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas-IVIC, Apartado 20632, Caracas 1020A, Venezuela. csevcik@ivic.gob.ve
authors.forename: Carlos
authors.initials: C
authors.lastname: Sevcik
authors.forename: Gina
authors.initials: G
authors.lastname: D'Suze
authors.forename: Víctor
authors.initials: V
authors.lastname: Salazar
authors.forename: Patricia
authors.initials: P
authors.lastname: Díaz
authors.forename: Hilda
authors.initials: H
authors.lastname: Vázquez
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D002462:Cell Membrane / Q000187:drug effects; D004912:Erythrocytes / Q000276:immunology*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D006736:Horses; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D007136:Immunoglobulins / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D020310:Struthioniformes
chemical_list: C016512:IgY; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007136:Immunoglobulins; D016650:Fluorescein-5-isothiocyanate