Retinoic acid and polyinosinic: Polycytidylic acid synergistically enhance the anti-tetanus IgG response in vitamin A-deficient rats

K. L. DeCicco, N. Q. Li, A. Catharine Ross

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Vitamin A (VA) deficiency reduces the antibody response to tetanus toxoid (TT), while treatment with retinoic acid (RA) reverses this immunodeficiency. In this study we tested the ability of RA and a potent interferon inducer, polyriboinosinic: polyribocytidylic acid stabilized with poly-1-lysine and carboxymethylcellulose (PIC), alone and in combination, to stimulate the anti-TT IgG response during VA deficiency. Male Lewis rats were fed either a purified VA- free diet (n=24) or were pair-fed the same diet containing adequate VA (n=6). When rats were 41 d old, the 24 VA-deficient rats (serum retinol < 0.2 μmol/L) were divided into four treatment groups: TT only; TT + 3 doses of 100 μg of RA orally beginning on the day of immunization; TT + 20 μg PIC ip on the day of immunization, or TT + both RA and PIC. The pair-fed control group received only TT. Ten d after primary immunization serum anti-TT IgG levels were determined by ELISA. The geometric means of the anti-TT IgG response (in U/ml) were: VA-sufficient, 7.9; VA-deficient, 2.0; RA-treated, 16.6; PIC, 5.3; both, 162.2. By 2-way ANOVA of log-transformed data, there were main effects of RA and PIC (p<0.0001), as well as an interaction (p=0.025). All rats were reimmunized (d 61), without other treatments. The secondary anti-TT IgG response (U/ml) was: VA-suf., 219; VA-def., 18.6; RA, 347; PIC, 30.9; both, 11,749. Main effects and the interaction between RA and PIC were highly significant. These data imply complementarity between the retinoid and cytokine signalling cascades in enhancing IgG production.

Original languageEnglish (US)
JournalFASEB Journal
Issue number5
StatePublished - Mar 20 1998


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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