The immune system is a highly complex orchestration of cells, organs, tissues and active molecules which interact in an elaborate and dynamic network to protect the body from infection. The immune system can be divided into two categories: the innate immune system and the adaptive immune system. Innate immunity is an immediate but non-specific response. Adaptive or acquired immunity involves a specific reaction to a pathogen which the immune system recognizes from a previous encounter. The process of acquired immunity is the basis for vaccination. Recent research has focused on the role of nutrition (foods and specific components of foods) in the responsiveness of the immune system to challenges. Vaccine-specific serum antibody production has been suggested as a highly suitable model to evaluate dietary intervention on the resistance to infection or to other immune system-related diseases.
The pneumococcal vaccine can reduce the incidence and/or severity of infections caused by Streptococcus pneumoniae : namely, pneumonia, otitis media, sinusitis and meningitis. The 23-valent vaccine contains 23 pneumococcal polysaccharide antigens (serotypes 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F and 33F. Although there are at least 90 distinct serotypes, these 23 serotypes accounted for 85% to 90% of invasive pneumococcal infections in the US. The 23-valent vaccine produces a humoral (antibody-mediated) response: inducing the production of antibody from B-lymphocytes in the absence of help from T-lymphocytes. The type and concentration of antibody produced is dependent on the site of exposure. Systemic administration results primarily in the generating of circulating immunoglobulin(Ig)G whereas mucosal antigenic challenge results in a more vigorous IgA response. In contrast to the 23-valent pneumococcal vaccine, a 7-valent vaccine conjugated to a nontoxic diphtheria protein (used for children younger than 5 years) will induce a T-cell response.
Studies on improvement of the response to the pneumococcal vaccine by adults include revaccination, the addition on conjugates to the vaccine and alternative antigenic substances. In addition, nutritional products have been tested on their effect on the response to vaccination. Supplementation with 200 mg/day vitamin E for 4 months to subjects at least 65 years of age caused a suggestive, but insignificant, increase in antibody response to the pneumococcal vaccine. Another study evaluated the effects of prebiotic fructo-oligosaccharides (70% raftilose and 30% raftiline) derived from inulin on the response by an elderly population (70 years old and above). In this study the response to vaccination with the influenza B and pneumococcal vaccines was not significantly increased.
Arabinogalactans are high molecular weight, highly branched, water-soluble polysaccharides, which contain units of D-galactose and L-arabinose. Arabinogalactans have previously demonstrated immunostimulatory activity[8, 9]. They are present in several immune-enhancing herbs, including Echinacea purpurea, Baptisia tinctoria, Thuja occidentalis, Angelica acutiloba, and Curucuma longa and the medicinal mushroom Ganoderma lucidum. [10–12]. Arabinogalactans from Larch (Larix spp.) have been shown to stimulate natural killer cell cytotoxicity in vitro through the generation of interferon gamma and inhibit the metastasis of tumor cells to the liver in a rodent model[7, 13, 14]. A dog study demonstrated increases in white blood cell counts (due to increases in neutrophils and eosinophils), and no effect on serum IgG, IgM or IgA following oral adminstration indoses of 0.55 g/day or 1.65 g/day for 10 days. A randomized, double-blind, placebo-controlled study evaluated the immunomodulating effects of a preparation of proprietary larch arabinogalactan (1.5 g/day) alone, and in combination with various preparations of Echinacea: an extract of Echinacea purpurea whole herb containing 4% phenolic compound (1.5 g/day), a preparation of E. purpurea whole herb and a preparation E. angustifolia root (36 to 680 mg/day). The study included 48 adult women who were divided into six groups of eight women. After 4 weeks of treatment, complement properdin increased by 18% in the group that received all four preparations and by 21% in the group given preparations of both species of Echinacea.
The current human clinical pilot study was designed to test the hypothesis that the ingestion of Resistaid™, a proprietary arabinogalactan extracted from Larch (Larix laricina), would selectively enhance the antibody response by adults to the 23-valent pneumococcal vaccine. Indications that the product would have immunostimulatory activity came from previous studies conducted with this proprietary product[15, 16]. As there was no prior human data regarding the ability of this proprietary arabinogalactan extract to impact the immune response to the pneumococcal vaccine, a power calculation could not be performed. The sample size was set at a level consistent with prior human studies involving arabinogalactan and the immune system[16–18].