Vaccination with a recombinant Saccharomyces cerevisiae expressing a tumor antigen breaks immune tolerance and elicits therapeutic antitumor responses

PURPOSE: Saccharomyces cerevisiae, a nonpathogenic yeast, has been used previously as a vehicle to elicit immune responses to foreign antigens, and tumor-associated antigens, and has been shown to reduce tumor burden in mice. Studies were designed to determine if vaccination of human carcinoembryonic antigen (CEA)-transgenic (CEA-Tg) mice (where CEA is a self-antigen) with a recombinant S. cerevisiae construct expressing human CEA (yeast-CEA) elicits CEA-specific T-cell responses and antitumor activity. EXPERIMENTAL DESIGN: CEA-Tg mice were vaccinated with yeast-CEA, and CD4(+) and CD8(+) T-cell responses were assessed after one and multiple administrations or vaccinations at multiple sites per administration. Antitumor activity was determined by tumor growth and overall survival in both pulmonary metastasis and s.c. pancreatic tumor models. RESULTS: These studies demonstrate that recombinant yeast can break tolerance and that (a) yeast-CEA constructs elicit both CEA-specific CD4(+) and CD8(+) T-cell responses; (b) repeated yeast-CEA administration causes increased antigen-specific T-cell responses after each vaccination; (c) vaccination with yeast-CEA at multiple sites induces a greater T-cell response than the same dose given at a single site; and (d) tumor-bearing mice vaccinated with yeast-CEA show a reduction in tumor burden and increased overall survival compared to mock-treated or control yeast-vaccinated mice in both pulmonary metastasis and s.c. pancreatic tumor models. CONCLUSIONS: Vaccination with a heat-killed recombinant yeast expressing the tumor-associated antigen CEA induces CEA-specific immune responses, reduces tumor burden, and extends overall survival in CEA-Tg mice. These studies thus form the rationale for the incorporation of recombinant yeast-CEA and other recombinant yeast constructs in cancer immunotherapy protocols.     

Involvement of TSC genes and differential expression of other members of the mTOR signaling pathway in oral squamous cell carcinoma

Background  

Despite extensive research, the five-year survival rate of oral squamous cell carcinoma (OSCC) patients has not improved. Effective treatment of OSCC requires the identification of molecular targets and signaling pathways to design appropriate therapeutic strategies. Several genes from the mTOR signaling pathway are known to be dysregulated in a wide spectrum of cancers. However, not much is known about the involvement of this pathway in tumorigenesis of OSCC. We therefore investigated the role of the tumor suppressor genes, TSC1 and TSC2, and other members of this pathway in tumorigenesis of OSCC.     

Cutaneous matastasis from sino-nasal malignant melanoma — a rare case report

To report a case of disseminated cutaneous metastasis from malignant melanoma of sino-nasal region. A 53-year-old man from rural parts of West Bengal presented with progressive nasal obstruction. CT scanning was done to know the extent of the mass and punch biopsy from the mass was performed. Malignant melanoma of sino-nasal region was diagnosed and chemotherapy was started. The patient developed cutaneous deposits after two cycles of chemotherapy. The patient developed cutaneous deposits during the course of chemotherapy. Excision biopsy from cutaneous deposits revealed malignant melanoma. A rare case of diffuse cutaneous metastasis of malignant melanoma is presented here along with review of literature.     

Differentiation of typhoid fever from fulminant hepatic failure in patients presenting with jaundice and encephalopathy

OBJECTIVE: To determine the clinical and laboratory features that allow the early diagnosis of typhoid fever in patients who present with jaundice and encephalopathy. PATIENTS AND METHODS: This 12-month prospective study, conducted in Bangalore, India, between 1990 and 1991, evaluated the clinical and laboratory features of all patients (N=47) who presented with encephalopathy within 8 weeks of onset of jaundice. Ciprofloxacin and dexamethasone were used to treat 11 patients diagnosed on blood culture as having typhoid fever. The other 36 patients were presumed to have fulminant hepatic failure with a viral cause and were treated with supportive measures (bioartificial liver support and transplantation were not available). RESULTS: In patients with jaundice and encephalopathy, a liver span of greater than 9 cm on physical examination, thrombocytopenia, elevated alkaline phosphatase level, aspartate aminotransferase level greater than alanine aminotransferase level, and only mild prolongation of the prothrombin time suggested a diagnosis of typhoid fever. All 11 patients diagnosed as having typhoid fever had an excellent response to treatment with ciprofloxacin and dexamethasone with no mortality and with normalization of the liver test results in 2 weeks. On the other hand, 30 of the 36 patients with nontyphoid fulminant hepatic failure died. CONCLUSIONS: In patients presenting with jaundice and encephalopathy, physical examination and simple laboratory tests can help make an early diagnosis of typhoid fever. We believe that patients with a presumptive diagnosis of typhoid fever should be treated with ciprofloxacin and dexamethasone, even before the results of blood cultures are available.     

Tracheostomy in the management of respiratory distress—A 10 years review

The role of 170 tracheostomies done over a period of 10 years (1982–1991) in the Department of Otorhinolaryngology at Silchar Medical College Hospital is analysed. Upper respiratory tract obstruction was found to be the commonest indication of operation. Most of the operations were carried out as an emergency and found to be a safe and life-saving procedure in the management of respiratory distress.     

Long-acting forms of Sonic hedgehog with improved pharmacokinetic and pharmacodynamic properties are efficacious in a nerve injury model

The therapeutic effects of the Sonic hedgehog (Shh) have been difficult to evaluate because of its relatively short serum half-life. To address this issue polyethylene glycol modification (PEGylation) was investigated as an approach to improve systemic exposure. Shh was PEGylated by a targeted approach using cysteines that were engineered into the protein by site-directed mutagenesis as the sites of attachment. Sixteen different versions of the protein containing one, two, three, or four sites of attachment were characterized. Two forms were selected for extensive testing in animals, Shh A192C, which provided a single site for PEGylation, and Shh A192C/N91C, which provided two sites. The PEGylated proteins were evaluated for reaction specificity by SDS-PAGE and peptide mapping, in vitro potency, pharmacokinetic and pharmacodynamic properties, and efficacy in a sciatic nerve injury model. Targeted PEGylation was highly selective for the engineered cysteines and had no deleterious effect on Shh function in vitro. Systemic clearance values in rats decreased from 117.4 mL/h/kg for unmodified Shh to 29.4 mL/h/kg for mono-PEGylated Shh A192C that was modified with 20 kDa PEG-maleimide and to 2.5 mL/h/kg for di-PEGylated Shh A192C/N91C modified with 2, 20 kDa PEG vinylsulfone adducts. Serum half-life increased from 1 h for unmodified Shh to 7.0 and 12.6 h for the mono- and di-PEGylated products. These changes in clearance and half-life resulted in higher serum levels of Shh in the PEG-Shh-treated animals. In Ptc-LacZ knock-in mice expressing lacZ under regulation of the Shh receptor Patched, about a 10-fold lower dose of PEG-Shh was needed to induce beta-galactosidase than for the unmodified protein. Therapeutic treatment of mice with PEG-Shh enhanced the regeneration of injured sciatic nerves. These studies demonstrate that targeted PEGylation greatly alters the pharmacokinetic and pharmacodynamic properties of Shh, resulting in a form with improved pharmaceutical properties.     

Targeted mass treatment for syphilis with oral azithromycin

From mid 1997 to end of 1999, there was a sexually-transmitted infectious syphilis outbreak mainly in heterosexual people in British Columbia, Canada, that was concentrated in Vancouver. The rate across the province increased from less than 0.5 to 3.4 per 100000, and the rate in Vancouver reached 12.9 per 100000. We aimed to eliminate the syphillis outbreak by treating people at risk of infection. In 2000, a targeted mass treatment programme provided azithromycin (1.8 g orally) to 4384 at-risk residents in this city. After the programme, syphilis frequency fell significantly for 6 months (p=0.016), but rose again in 2001. Results from curve fitting analyses showed that the number of cases in 2001 (177) was higher than expected (0.0001相似文献   

Salmonella pathogenicity island-2 and anticancer activity in mice

Salmonella enterica servovar Typhimurium is capable of targeting, colonizing, and eliciting growth suppression of tumors in mice. We examined the effects of mutations on this anticancer phenotype in two Salmonella virulence gene clusters. Salmonella pathogenicity island (SPI)-1 genes promote systemic invasion from the intestine, whereas SPI-2 genes support systemic survival within macrophages and other cells. Disabling SPI-1 (prgH(-)) strongly reduced invasion in vitro, but had no effect on tumor growth suppression in vivo. However, disabling SPI-2 (ssaT(-)) ablated tumor growth suppression. In addition to ssaT(-), mutations in SPI-2 genes sseA, sseB, sseC, sscA, and ssrA also eliminated antitumor activity, whereas mutations in sseF or sseG yielded partial loss of function. Impaired tumor amplification was seen in three SPI-2 mutants tested after intravenous or intratumoral injection. A SPI-2(-) strain was unable to suppress tumor growth in CD18-deficient mice with defective macrophages and neutrophils, suggesting that loss of tumor growth suppression in wild-type mice by SPI-2 mutants was not solely a function of increased susceptibility to immune attack. Thus, SPI-2 is essential for the Salmonella antitumor effects, perhaps by aiding bacterial amplification within tumors, and is the first identified genetic system for this Salmonella phenotype.     

Tuberculosis and HIV illness

The HIV infection leading to AIDS is considered to be one of the greatest biomedical challenges in the present century. Like all other communicable diseases AIDS is gradually penetrating the underprivileged sections of society in all countries. Nearly 5 million people in India are living with AIDS at present that makes India a single country with highest number of HIV infected people in the world. The hallmark of HIV disease is the reduction of CD4+ T-lymphocytes, the key cells of immunity. The initial phase of the disease may be termed as HIV seroconversion illness. The next phase is termed asymptomatic HIV infection. When the CD4 count falls below 400/microliter, the patient develops early opportunistic infections which may be termed as early symptomatic HIV infection or AIDS related complex (ARC). Mycobacterial infections are also common in these patients and have led to an alarming resurgence of tuberculosis (TB) in many countries. The available information suggests that TB may be the commonest HIV related disease in the world. The clinical presentation of TB in HIV infected individual is influenced by the degree of HIV related immunosuppression. The atypical features like extrapulmonary TB and absence of positive Mantoux test are generally noticed at a fairly advanced stage. The x-ray chest is also an important adjunct to diagnosis of TB in HIV infected individual. The studies on TB and AIDS in the early part of HIV epidemic in developed countries suggest that extrapulmonary TB is more common in co-infected people but when TB infection is considered in all HIV infected persons, extrapulmonary TB is less common than pulmonary TB. The result of treatment in co-infected pulmonary TB cases is almost similar with the cases suffering from TB alone. Treatment failure, however, has been noticed rarely at extrapulmonary sites.