Pathology of reversed passive Arthus reaction in the chicken

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Increased vascular permeability and leucocyte emigration in Escherichia coli endotoxin injury in the chicken skin

The permeability response was examined in chickens following intradermal injection of Escherichia coli endotoxin. The 'dye' and 'colloidal carbon' techniques were employed. The endotoxin evoked a monophasic response of immediate-prolonged type. The increase in vascular permeability was confined to venules and small veins only, indicating its mediation by endogenous permeability factors. The carbon labelling exhibited arboreal, disjointed and rectangular to hexagonal patterns. Histologically, a striking feature of the reaction was an accumulation of basophils in unusually large numbers. No other type of stimulus appears to induce basophilic response of a similar magnitude in the chicken. The results suggest that endotoxin, being a bacterial product, may exert a chemotactic effect on basophils. Hyperaemia, oedema, necrosis and formation of perivascular lymphoid aggregates were also recognised.

A microscopic study of increased vascular permeability and leucocyte emigration in passive cutaneous anaphylaxis in the chicken

Passive cutaneous anaphylaxis was produced in chickens with bovine serum albumin (BSA) and anti-BSA chicken serum. Colloidal carbon was then given intravenously to identify the leaky vessels. Examination of the resulting sequential changes revealed a marked increase in vascular permeability affecting the venules. A noteworthy feature of the reaction was the early participation of the basophils, which contained phagocytosed carbon particles. Eosinophils were absent.

Quantitative estimation of increased vascular permeability in acute inflammatory reaction in the chicken skin

An increase in vascular permeability was estimated quantitatively in acute inflammatory reaction in the chicken using passive cutaneous anaphylaxis as an experimental model. Dye exuded in the cutaneous lesion was extracted by formamide and measured spectrophotometrically. The technique, though time-consuming, worked well in the chicken. The results suggested that the method can be profitably utilised in studies relating to avian inflammation.

A topographical study of increased vascular permeability in passive cutaneous anaphylaxis in the chicken

Passive cutaneous anaphylaxis was produced in chickens with bovine serum albumin (BSA) and anti-BSA chicken serum. Colloidal carbon was then given intravenously to identify the leaky vessels. Microscopic examination of cleared unstained skin revealed the topography of labelled vessels. The carbon labelling was confined to venules and small veins only. Examination of the time-course of permeability response revealed a biphasic pattern.