Dextran sulphate: an adjuvant for cell-mediated immune responses

Area of Science:

• Immunology
• Pharmacology

Background:

• Cell-mediated immunity plays a crucial role in host defense against pathogens.
• Delayed-type hypersensitivity (DTH) is a key component of cell-mediated immunity.
• Adjuvants are substances that augment the immune response to an antigen.

Purpose of the Study:

• To investigate the effect of high molecular weight dextran sulphate (DS) on cell-mediated immune responses.
• To determine if DS can enhance delayed-type hypersensitivity (DTH) in animal models.
• To identify optimal conditions for DS administration to achieve immune augmentation.

Main Methods:

• Assessed DTH using three criteria: footpad swelling, intradermal skin tests, and macrophage migration inhibitory factor (MIF) production.
• Utilized guinea-pigs sensitized with egg albumin (EA) and mice sensitized with EA or sheep red blood cells (SRBC).
• Administered varying doses and timings of DS in relation to antigen sensitization and challenge.

Main Results:

• DS treatment led to strong positive delayed skin tests in guinea-pigs sensitized with EA.
• DS increased MIF production in lymphocytes from mice sensitized with EA.
• DS significantly augmented delayed footpad swelling responses in mice sensitized with SRBC, particularly when administered subcutaneously at the same site as SRBC, up to 6 days prior, with optimal enhancement observed 2 days before SRBC.

Conclusions:

• High molecular weight dextran sulphate (DS) is a potent adjuvant for cell-mediated DTH immune responses.
• DS effectively enhances DTH in both guinea-pigs and mice.
• The timing and route of administration of DS are critical for its adjuvant activity.