Licensure and limited occupational use (1970-1991)
In 1970, AVA was first licensed by the USPHS for protection against cutaneous anthrax to a state-owned facility operated by the Michigan Department of Public Health. In 1973, the US Food and Drug Administration (FDA) first published standards for making, using and storing AVA. In the mid-1980s, the FDA approved it specifically for two limited preventive indications: 1) individuals who may come in contact with animal products or high-risk persons such as veterinarians and others handling potentially infected animals; and 2) individuals engaged in diagnostic or investigational activities involving anthrax spores. In 1985, the FDA published a Proposed Rule for a specific product review of the AVA, stating that the vaccines "efficacy against inhalation anthrax is not well documented" (a statement quoted controversially many years later). For many years, AVA was a little known product considered to be safe for pre-exposure use in the US in at-risk veterinarians, laboratory workers, livestock handlers, and textile plant workers who process animal hair. In 1990, the State of Michigan changed the name of its original production plant facility to the Michigan Biologic Products Institute (MBPI) as it gave up state ownership and converted it to a private entity.
This possibility increased interest in the effect of chronic morphine use on the immune system. The first step of determining that morphine may affect the immune system was to establish that the opiate receptors known to be expressed on cells of the central nervous system are also expressed on cells of the immune system. One study successfully showed that dendritic cells, part of the innate immune system, display opiate receptors. Dendritic cells are responsible for producing cytokines, which are the tools for communication in the immune system. This same study showed that dendritic cells chronically treated with morphine during their differentiation produce more interleukin-12 (IL-12), a cytokine responsible for promoting the proliferation, growth, and differentiation of T-cells (another cell of the adaptive immune system) and less interleukin-10 (IL-10), a cytokine responsible for promoting a B-cell immune response (B cells produce antibodies to fight off infection).This regulation of cytokines appear to occur via the p38 MAPKs (mitogen-activated protein kinase)-dependent pathway. Usually, the p38 within the dendritic cell expresses TLR 4 (toll-like receptor 4), which is activated through the ligand LPS (lipopolysaccharide). This causes the p38 MAPK to be phosphorylated. This phosphorylation activates the p38 MAPK to begin producing IL-10 and IL-12. When the dendritic cells are chronically exposed to morphine during their differentiation process then treated with LPS, the production of cytokines is different. Once treated with morphine, the p38 MAPK does not produce IL-10, instead favoring production of IL-12.