Immune adherence was described by Nelson (1953) for an ''in vitro'' immunological reaction between normal

erythrocyte Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood ce ...

s and a wide variety of microorganisms sensitized with their individually specific

antibody An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as pathogenic bacteria, bacteria and viruses, includin ...

and

complement Complement may refer to: The arts * Complement (music), an interval that, when added to another, spans an octave ** Aggregate complementation, the separation of pitch-class collections into complementary sets * Complementary color, in the visu ...

; erythrocytes were observed to adhere to microorganisms. It was later recognized to occur ''in vivo.'' The phenomenon is now resolved as a complement-dependent binding reaction of erythrocytes to microorganisms where specific antibodies are engaged in the process.Roitt IM, Brostoff J, Male D (1998). ''Immunology, 5th ed.'' London: Mosby, . The reaction process is as follows: any microorganisms are bound with their specific antibodies, if they are produced, which activate the

classical pathway The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune system. The classical complement pathway is initiated by antigen-antibody complexes with the antibody isotypes IgG and I ...

of the complement system. The cascade begins to work from C1 to

C3b C3b is the larger of two elements formed by the cleavage of complement component 3, and is considered an important part of the innate immune system. C3b is potent in opsonization: tagging pathogens, immune complexes (antigen-antibody), and apoptot ...

through C4b, C3b being further transformed to

iC3b iC3b is a protein fragment that is part of the complement system, a component of the vertebrate immune system. iC3b is produced when complement factor I cleaves C3b.Robbins Basic Pathology 8th ed 2007. R Cotran, S Robbins, V Kumar, J Perkins. W.B ...

(inactive derivative of C3b), all of which, C4b and thereafter, remain to bind to the surface of the microbe. Because primate erythrocytes express

complement receptor 1 Complement receptor type 1 (CR1) also known as C3b/C4b receptor or CD35 (cluster of differentiation 35) is a protein that in humans is encoded by the ''CR1'' gene. This gene is a member of the regulators of complement activation (RCA) family a ...

(CR1) on their surface and having binding specificity to C4b, C3b, or iC3b, erythrocytes accumulate on the microbe via CR1-complement binding.Frank K, Atkinson JP (2001). "Complement system." In Austen KF, Frank K, Atkinson JP, Cantor H. eds. ''Samter's Immunologic Diseases, 6th ed. Vol. 1,'' p. 281–298, Philadelphia: Lippincott Williams & Wilkins,

Function of the immune adherence (''in vivo'')

Human erythrocytes express 100 to 1,000 CR1 per cell, the average number of approximately 300 being an inherited characteristics. Immune complexes bound to erythrocytes are effectively removed from the circulation, which is presumed alternatively to prevent deposition at tissue sites, for example, the renal glomerulus. Erythrocytes bearing immune complexes traverse sinusoids of the

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

and spleen, where they encounter fixed

phagocyte Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s. Phagocytes expressing CR1, CR3, and Fcγ receptors effect a transfer of the immune complexes to their surface. Then erythrocytes leave the liver and spleen bearing off immune complexes and work on the next round of transfer of immune complexes after adhering to them.Bala Subramanian V, Liszewski MK, Atkinson JP (2000). "The complement system and autoimmunity." In Lahita RG, Chiorazzi N, Reeves WH, eds. ''Textbook of the Autoimmune Diseases.'' Philadelphia: Lippincott Williams & Wilkins, .

References

{{Reflist Immunology Immune system