<unk>  in not currently available but is under study. Obstacles Variability of immunogenicity In order for an immunocontraceptive to be palatable for human use, it would need to meet or exceed the efficacy rates of currently popular forms of contraception. Currently the maximum reduction of fertility due to sperm vaccines in laboratory experiments with mice is ~75%. The lack of efficacy is due to variability of immunogenicity from one animal to another. Even when exposed to the exact same vaccine, some animals will produce abundant antibody titers to the vaccine's antigen, while others produce relatively low antibody titers. In the Eppin trial that attained 100% infertility, a small sample size (only 9 monkeys) was used, and even among this small sample 2 monkeys were dropped from the study because they failed to produce sufficiently high antibody titers. This trend—high efficacy when antibody titers are above a threshold coupled with variability in how many animals reach such a threshold—is seen throughout<unk>  and immune-based birth control research. A long-term study of PZP vaccination in deer that spanned 6 years found that infertility was directly related to antibody titers to PZP. The phase II clinical trial of hCG vaccines was quite successful among women who had antibody titers above 50 ng/mL, but quite poor among those with antibody titers below this threshold. Lack of mucosal immunity Mucosal immunity, which includes immune function in the female reproductive tract, is not as well understood as humoral immunity. This may be an issue for certain contraceptive vaccines. For instance, in the second LDH-C4 primate trial that had negative results, all of the immunized macaque monkeys developed high antibody titers against LDH-C4 in serum, but antibodies against LDH-C4 were not found in the monkeys' vaginal fluids. If antibodies against LDH-C4 do indeed inhibit fertilization, then this result highlights how the difference in the functioning of mucosal immunity from humoral immunity may be critical to the efficacy of contraceptive vaccines.
Immunocontraception
Cardioprotection
Neuroprotection
Hepatoprotection
Nociception
Ovulation induction
Immunostimulant
Digestion