Fructans from aged garlic extract produce a delayed immunoadjuvant response to ovalbumin antigen in BALB/c mice

Abstract

Garlic (Allium sativum) is known for its innumerable biological activities including immunomodulation. Aged garlic extract (AGE), an odorless garlic preparation, has been shown to have superior immunomodulatory properties over raw garlic extract. Although garlic is a very rich source of fructans (17%, fresh weight basis), AGE contains only 0.22% of raw garlic fructans. Aged garlic fructans (AGF) have recently been shown to possess immunomodulatory activities in vitro. Natural adjuvants capable of eliciting better immune response of a model antigen are important in developing newer vaccines. In the present study, the adjuvant activity of AGF has been investigated in BALB/c mice using ovalbumin (OVA, 30 µg) as an experimental antigen. The body weights of animals did not change significantly indicating that the administration of garlic fructans is well-tolerated. AGF produce a significant humoral (serum IgG) response to OVA in BALB/c mice administered mucosally by either intranasal or oral route—a delayed response appearing on 50th day at a dose of 30 µg AGF by intranasal route. However, the serum IgG response was seen earlier on 35th day at a dose of 100 µg AGF by oral route. Higher concentrations of AGF (>50 µg) were inhibitory for adjuvant activity by intranasal administration. These observations indicate that AGF display immunoadjuvant activity for a test antigen though the humoral immune response is delayed.

Keywords::

• Aged garlic fructans
• BALB/c mice
• IgG response
• immunoadjuvant
• mucosal administration
• ovalbumin
• polysaccharide adjuvant

Acknowledgements

This study was supported by the Council of Scientific & Industrial Research (CSIR), New Delhi in the form of an institutional project (MLP-057) to YPV. PMC thanks the Indian Council of Medical Research (ICMR), New Delhi, for the award of a senior research fellowship (IRIS ID No. 2006-04440).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.