Caerin 1.20

Antibiotic resistance-related bacterial infections and cancers become huge challenges in human health in the 21st century. A number of naturally derived antimicrobial peptides possess multiple functions in host defense, including anti-infective and anticancer activities. One of which is known as the caerin 1 family peptides. The microbicidal properties of these peptides have been long discussed. The recent studies also established the usage of two members in this family, caerin 1.1 and caerin 1.9, in antimultiple antibiotic-resistant bacteria species. It is increasingly evident that caerin 1.1 and caerin 1.9 also contain additional activities in the suppression of tumor. In this review, we briefly outline the therapeutic potentials and possible mechanism of action of caerin 1.1 and 1.9 in the treatment of multiple antibiotic-resistant bacterial infection and cancer immunotherapy.

Topical antimicrobicides hold great promise in reducing human immunodeficiency virus (HIV) transmission. Amphibian skin provides a rich source of broad-spectrum antimicrobial peptides including some that have antiviral activity. We tested 14 peptides derived from diverse amphibian species for the capacity to inhibit HIV infection. Three peptides (caerin 1.1, caerin 1.9, and maculatin 1.1) completely inhibited HIV infection of T cells within minutes of exposure to virus at concentrations that were not toxic to target cells. These peptides also suppressed infection by murine leukemia virus but not by reovirus, a structurally unrelated nonenveloped virus. Preincubation with peptides prevented viral fusion to target cells and disrupted the HIV envelope. Remarkably, these amphibian peptides also were highly effective in inhibiting the transfer of HIV by dendritic cells (DCs) to T cells, even when DCs were transiently exposed to peptides 8 h after virus capture. These data suggest that amphibian-derived peptides can access DC-sequestered HIV and destroy the virus before it can be transferred to T cells. Thus, amphibian-derived antimicrobial peptides show promise as topical inhibitors of mucosal HIV transmission and provide novel tools to understand the complex biology of HIV capture by DCs.

Although acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) is a manageable disease for many, it is still a source of significant morbidity and economic hardship for many others. The predominant mode of transmission of HIV/AIDS is sexual intercourse, and measures to reduce transmission are needed. Previously, we showed that caerin 1 antimicrobial peptides (AMPs) originally derived from Australian amphibians inhibited in vitro transmission of HIV at relatively low concentrations and had low toxicity for T cells and an endocervical cell line. The use of AMPs as part of microbicidal formulations would expose the vaginal microbiome to these agents and cause potential harm to protective lactobacilli. Here, we tested the effects of caerin 1 peptides and their analogs on the viability of two species of common vaginal lactobacilli (Lactobacillus rhamnosus and Lactobacillus crispatus). Several candidate peptides had limited toxicity for the lactobacilli at a range of concentrations that would inhibit HIV. Three AMPs were also tested for their ability to inhibit growth of Neisseria lactamica, a close relative of the sexually transmissible Neisseria gonorrhoeae. Neisseria lactamica was significantly more sensitive to the AMPs than the lactobacilli. Thus, several candidate AMPs have the capacity to inhibit HIV and possible N. gonorrhoeae transmission at concentrations that are significantly less harmful to the resident lactobacilli.