Establishment of a ICR mouse model of systemic C. albicans infection induced by oral inoculation / 中国实验动物学报

Objective To establish a mouse model of systemic C. albicans infection by oral inoculation of the pathogen and observe the proliferation and distribution of C. albicans in vivo tissues. Methods Male ICR mice(n=46) were used as the experiment group(n=40) and blank group (n=6). Cotton swabs with C. albicans were used to infect the mice (7 × 106 CFU/mL), and the blank group with saline. The mice of the experiment group were randomly divided into two groups:model group A for clinical assessment (n=20) and model group B for tissue fungal burden detection (n=20). Clinical score, survival and autopsy were carried out among the model group A. Five mice were randomly killed from the model group B at 3 d, 5 d and7 d after infection, respectively ( blank group killed 2 mice each time) . Microbial load tablet method was used to detect the tissue fungal burdens in different tissues, meanwhile samples of tongue, esophagus, stomach, liver, kidney, lung of infected mice were taken for pathological examination. Results White spot appeared on the surface of tongue since 3 d postinfection and increased with time and finally caused death. The mortality reached over 50% at 5 d. C. albicans was not only detected from the tongue (87?5%), stomach (87?5%), liver (54?5%), kidney (50?5%), lung (20%) and heart (4%), but also was microscopically seen mycelia proliferation in the tongue, stomach, liver, and kidney , yet not seen in the control group, showing that C. albicans caused disseminated systemic infection through mucosal infection in mice. Conclusions C. albicans can induce opportunistic systemic infection by breakthrough the mucosal immune barrier, so as to increase the infection to death.

Prophylactic and Therapeutic Modulation of Innate and Adaptive Immunity Against Mucosal Infection of Herpes Simplex Virus

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, CD4+ Th1 T cells producing IFN-gamma are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.

Glutamine and Leucine Provide Enhanced Protective Immunity Against Mucosal Infection with Herpes Simplex Virus Type 1

Besides their role as building blocks of protein, there are growing evidences that some amino acids have roles in regulating key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. Here, we evaluated the modulatory functions of several amino acids in protective immunity against mucosal infection of herpes simplex virus type 1 (HSV-1). We found that glutamine (Gln) and leucine (Leu) showed enhanced protective immunity to HSV-1 mucosal infection when two administration of Gln and single administration of Leu per day, but not when administered in combinations. Ameliorated clinical signs of HSV-1 challenged mice by the intraperitoneal administration of Gln and Leu were closely associated with viral burden and IFN-gamma production in the vaginal tract at 2 and 4 days post-infection. In addition, the enhanced production of vaginal IFN-gamma appeared to be caused by NK and HSV-1 antigen-specific Th1-type CD4+ T cells recruited into vaginal tract of mice treated with Gln and Leu, which indicates that IFN-gamma, produced by NK and Th1-type CD4+ T cells, may be critical to control the outcome of diseases caused by HSV-1 mucosal infection. Collectively, our results indicate that intraperitoneal administration of Gln and Leu following HSV-1 mucosal infection could provide beneficial effects for the modulation of protective immunity, but dosage and frequency of administration should be carefully considered, because higher frequency and overdose of Gln and Leu, or their combined treatment, showed detrimental effects to protective immunity.