Delayed hypersensitivity reactions in guinea‐pigs using cotton pellets; Demonstration of macrophage migration inhibition activity in the cell free exudate

Abstract

Subcutaneous implantation of cotton pellets containing PPD into CFA sensitised guinea-pigs produced a reaction of having many characteristics of the delayed hypersensitivity (DH) reaction, together with less conspicuous features of a non-immunological response. The time course of the cellular response in the reaction showed a slow onset, attaining maximum levels between 18 and 24 hr. Mononuclear cells dominated the reaction from 18 to 48 hr. In animals treated with ALS the reaction diminished to the level of a non-immunological reaction. The model made it possible to detect macrophage migration inhibition factor (MIF) activity in the skin exudates. From 6--48 hr high molecular weight antigen-dependent MIF activity was found associated with immunoglobulin. At 18 hr, two types of low molecular weight MIF activity were demonstrated. One was antigen-dependent and the other was antigen-independent. Treatment of sensitised guinea-pigs with ALS abolished the appearance of these factors, suggesting that they might be related to cell-mediated immunity. At 48 hr, the low molecular weight antigen-dependent MIF activity was still evident whereas the low molecular weight antigen-independent activity was not detected. High molecular weight antigen-independent MIF activity was also found at 18 hr. No MIF activity was demonstrated in any of the control exudates.

Demonstration of Accelerated and Increased Migration Inhibition Factor Release in vivo in a PPD Retest Reaction

“…Technically, it is rather difficult to obtain exudate fluids from skin test reactions [6,24], In our opinion, the cotton pellet model recently introduced by Yamamoto and Ishikura [25] is no solution to this problem, as the (antigen-containing) cotton pellets are implanted sub cutaneously, thereby creating a new tissue compart ment. Therefore, we decided to study a possible role of lymphokines in retest reactivity in a peritoneal in flammation model, the advantages of which have been discussed earlier [1 I], One should note that retest reactivity in this model cannot be compared with a virgin site on the same animal and, therefore, may show simply a booster effect of the second antigen ap plication.…”

“…A similar so-called 'retest reactivity' has been observed with other antigens, e.g., tetanus, ovalbumin (OA) and DNP-conjugated gui nea pig albumin [1,9], as well as epicutaneously ap plied DNCB [14]. Retest reactivity might be due to the local persistence of antibody-producing cells as it was suggested to play a role in 'flare-up' reactions [16], but might also be due to the local retention of sensitized T lymphocytes at the site of the old reaction [3,14,17], A primary role of a T cell-mediated mechanism is likely as retest reactions can be observed in delayed hypersensitivity (DH) animals in the absence of circu lating antibodies [9], As T cell-mediated hypersensitivity reactions are now known to be mediated by lymphokines [11,18,20,25,26], we decided to verify whether an accelerat ed local lymphokine release in vivo could account for retest reactivity. For this purpose experiments were designed in which both primary and retest reactions were induced in the peritoneal cavity of guinea pigs.…”