Delayed Hypersensitivity in Mice to Dextran

Abstract

Mice injected subcutaneously with native high molecular weight dextran emulsified in either complete or incomplete Freund adjuvant develop delayed hypersensitivity to this antigen unaccompanied by either Arthus or anaphylactic hypersensitivities. Delayed cutaneous reactions in mice hypersensitive to dextran differ histologically from the usual concept of delayed-type reactions in that among the infiltrating cells constituting the indurated reaction polymorphonuclear cells outnumber monocytes, although the latter are present in large numbers. Dextran hypersensitivity was transferable passively in these experiments with lymphoid cells, but no form of hypersensitivity to it could be transferred with antiserum. When intravenously injected Evans blue dye was employed to detect vascular permeability increases in skin-test regions in both actively and passively sensitized mice, only a faint annular bluing was observed; this developed only in mice injected with the dye 24 hr. after skin-testing. Incidentally, injecting this dye within 3 hr. after skin-testing blocked development of induration of the dextran reaction. Cortisone acetate interfered with the dextran reaction in weakly but not in strongly sensitized mice; neither an antihistaminic nor an antiserotonin had any effect.