Sheep macrophages express at least two distinct receptors for IgG which have similar affinity for homologous IgG1 and IgG2.

Jungi, Thomas; Francey, Thierry; Brcic, Marija; Pohl, B; Peterhans, Ernst (1992). Sheep macrophages express at least two distinct receptors for IgG which have similar affinity for homologous IgG1 and IgG2. Veterinary immunology and immunopathology, 33(4), pp. 321-337. Elsevier

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Ovine bone marrow-derived macrophages (BMM) may express several IgG receptor (Fc gamma receptor; FcR) subsets. To study this, model particles (opsonized erythrocytes; EA), which are selectively handled by certain FcR subsets of human macrophages were used in cross-inhibition studies and found to react in a similar manner with FcR subsets of sheep macrophages. In experiments with monoclonal antibodies against subsets of human FcR, human erythrocytes (E) treated with human anti-D-IgG (anti-D-EAhu) and sheep E treated with bovine IgG1 (Bo1-EAs) were handled selectively by human macrophage FcRI and FcRII, respectively. Rabbit-IgG-coated sheep E (Rb-EAs) were recognized by FcRI, FcRII and possibly also by FcRIII of human macrophages. Anti-D-EAhu, Bo1-EAs and Rb-EAs were also ingested by sheep BMM. Competitive inhibition tests, using various homologous and heterologous IgG isotypes as fluid phase inhibitors and the particles used as FcR-specific tools in man (anti-D-EAhu and Bo1-EAs), revealed a heterogeneity of FcR also in sheep BMM. Thus, ingestion of anti-D-EAhu by ovine BMM was inhibited by low concentrations of competitor IgG from rabbit or man in the fluid phase, but not at all by bovine IgG1, whereas ingestion of Bo1-EAs was inhibited by bovine IgG1. This suggested that anti-D-EAhu were recognized by a FcR subset distinct from that recognizing bovine-IgG1. It was concluded that sheep BMM express functional analogs of human macrophage FcRI and FcRII and that Bo1-EAs and anti-D-EAhu are handled by distinct subsets of BMM FcR. All EAhu tested (EAhu treated with anti-D, sheep IgG1 or sheep IgG2) were ingested to a lower degree than EAs. This inefficient phagocytosis could be enhanced by treatment of EAhu with antiglobulin from the rabbit, suggesting that it is caused by a low degree of activity of opsonizing antibodies rather than special properties of the erythrocytes themselves. Several lines of evidence suggested that both FcR subsets of ovine BMM recognize both ovine IgG1 and IgG2. In contrast, bovine IgG1 reacts with one FcR subset and bovine IgG2 interacts inefficiently with all FcR of ovine BMM.

Item Type:	Journal Article (Original Article)
Division/Institute:	05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > Small Animal Clinic > Small Animal Clinic, Internal Medicine 05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Virology and Immunology
UniBE Contributor:	Jungi, Thomas, Francey, Thierry, Brcic, Marija, Peterhans, Ernst
Subjects:	600 Technology > 610 Medicine & health 600 Technology > 630 Agriculture
ISSN:	0165-2427
Publisher:	Elsevier
Language:	English
Submitter:	Thierry Francey-Spicher
Date Deposited:	27 Oct 2014 14:52
Last Modified:	05 Dec 2022 14:37
PubMed ID:	1441218
URI:	https://boris.unibe.ch/id/eprint/59591