Synthetic and natural immunomodulators acting as interferon inducers.

Interferons are first immunomodulatory molecules that have been shown to display a wide range of applications due to their antiviral, antibacterial, antitumor, and inflammatory activities. Natural and recombinant interferons are among most common biologic therapeutics worldwide. Interferon inducers, however, are less known and have been mostly developed and used in former socialist countries. Despite the fact that they are virtually unknown to the Western world, they represent a substantial market share of modern pharmacopoeia in former socialist republics. This review provides a brief description of most popular interferon inducers including Amyxin, Amizon, Anandin, Arbidol, Blasten, Cycloferon, Galavit, Groprinosine, Hepon, Immunoxel, Dzherelo, Kagocel, Larifan, Ligfol, Likopid, Mebavin, MIGI-KLP, V-5 Immunitor, SCV-07, Milife, Neovir, Poludan, Ragocin, Ridostin, Thymogen and Savratz, some of which were in use for several decades for the same clinical indications as for interferons. The variety and choice offered by the pharmaceutical industry behind the former "iron curtain" certainly deserves the appreciation, familiarity and application prospects for medical and research investigators worldwide.

Oral vaccination: where we are?

As early as 900 years ago, the Bedouins of the Negev desert were reported to kill a rabid dog, roast its liver and feed it to a dog-bitten person for three to five days according to the size and number of bites [1] . In sixteenth century China, physicians routinely prescribed pills made from the fleas collected from sick cows, which purportedly prevented smallpox. One may dismiss the wisdom of the Bedouins or Chinese but the Nobel laureate, Charles Richet, demonstrated in 1900 that feeding raw meat can cure tuberculous dogs - an approach he termed zomotherapy. Despite historical clues indicating the feasibility of oral vaccination, this particular field is notoriously infamous for the abundance of dead-end leads. Today, most commercial vaccines are delivered by injection, which has the principal limitation that recipients do not like needles. In the last few years, there has been a sharp increase in interest in needle-free vaccine delivery; new data emerges almost daily in the literature. So far, there are very few licensed oral vaccines, but many more vaccine candidates are in development. Vaccines delivered orally have the potential to take immunization to a fundamentally new level. In this review, the authors summarize the recent progress in the area of oral vaccines.

Improved immunogenicity of a self tumor antigen by covalent linkage to CD40 ligand.

The interaction between the CD40 ligand (CD40L) and CD40 on antigen-presenting cells (APCs) is critical in promoting humoral and cellular immune responses. Agonistic anti-CD40 monoclonal antibody and soluble CD40L can act as powerful adjuvants to promote vaccination, but usually require repeated high-dose treatment. In this study, we demonstrate that the adjuvant effect of CD40L can be greatly improved by directly linking the antigen to CD40L. We constructed a fusion protein (Id-CD40L) consisting of the extracellular domain of CD40L and the idiotype (Id) protein, a weakly immunogenic tumor-specific antigen derived from the murine 38C13 B-cell lymphoma. The soluble Id-CD40L fusion protein retained CD40 binding activity and stimulated CD80 and CD86 upregulation and interleukin (IL)-12 production by macrophages. Immunization of mice with Id-CD40L without adjuvants resulted in high titers of anti-Id Abs dominated by the IgG1 isotype and protected the mice from subsequent lethal tumor challenge. In a dose-response study, we demonstrated that Id-CD40L elicited anti-Id antibody (Ab) responses in all immunized animals, even at a dose as low as 0.5 microg. Immunization with free Id and an IgG-CD40L fusion protein, which was identical in structure to Id-CD40L but lost the Id determinant, resulted in significant lower anti-Id responses, indicating that physical linkage between the tumor antigen and CD40L was required for the optimal immune response. These results demonstrate that fusing CD40L to a candidate antigen can greatly improve the adjuvant activity of CD40L. This approach may be useful in developing vaccines for a variety of malignant and infectious diseases.