Richard Winn

Vaccines and Immunotherapeutics for the Treatment of Malignant Disease

The employment of the immune system to treat malignant disease represents an active area of biomedical research. The specificity of the immune response and potential for establishing long-term tumor immunity compels researchers to continue investigations into immunotherapeutic approaches for cancer. A number of immunotherapeutic strategies have arisen for the treatment of malignant disease, including various vaccination schemes, cytokine therapy, adoptive cellular therapy, and monoclonal antibody therapy. This paper describes each of these strategies and discusses some of the associated successes and limitations. Emphasis is placed on the integration of techniques to promote optimal scenarios for eliminating cancer.

Catastrophic antiphospholipid syndrome in a community-acquired methicillin-resistant Staphylococcus aureus infection: A review of pathogenesis with a case for molecular mimicry

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has remarkable pathogenicity and can cause severe infections, such as necrotizing pneumonia, necrotizing fasciitis, and sepsis. To our knowledge, no case of CA-MRSA resulting in catastrophic antiphospholipid syndrome (CAPS) has been reported. Furthermore, no specific pathogenic link between these two disorders has been described. Staphylococcal sequence homologies and binding capabilities to plasma protein β2-glycoprotein I (β2-GPI) may result in anti-β2-GPI antibody production. These antibodies represent the critical prothrombotic factor in pathogenesis of antiphospholipid syndrome and CAPS. However, the development of CAPS requires additional prothrombotic activities. In our case, sepsis and CA-MRSA-induced leukocytolysis likely represent the activity required to transform a hypercoagulable state into the life threatening, diffusely thrombotic CAPS. The presence of anti-β2GPI-antibodies and diffuse microvascular occlusion are characteristic of CAPS. However, other life threatening syndromes cause microvascular thrombi and multiorgan failure, and more studies are needed to determine the frequency of antiphospholipid antibodies and clinical syndromes consistent with CAPS in patients with staphylococcal infections.

Role of the Innate Immune Response and Tumor Immunity Associated with Simian Virus 40 Large Tumor Antigen

ABSTRACT We examined properties of the innate immune response against the tumor-specific antigen simian virus 40 (SV40) large tumor antigen (Tag) following experimental pulmonary metastasis in naive mice. Approximately 14 days after mKSA tumor cell challenge, expression of inflammatory mediators such as tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), and RANTES was upregulated in splenocytes harvested from mice, as assessed by flow cytometry and antibody array assays. This response was hypothesized to activate and induce tumor-directed NK cell lysis since IL-2-stimulated NK cells mediated tumor cell destruction in vitro. The necessary function of NK cells was further validated in vivo through selected antibody depletion of NK cells, which resulted in an overwhelming lung tumor burden relative to that in animals receiving a control rabbit IgG depletion regimen. Interestingly, mice achieved increased protection from experimental pulmonary metastasis when NK cells were further activated indirectly through in vivo administration of poly(I:C), a Toll-like receptor 3 (TLR3) agonist. In a separate study, mice receiving treatments of poly(I:C) and recombinant SV40 Tag protein immunization mounted effective tumor immunity in an established experimental pulmonary metastasis setting. Initiating broad-based immunity with poly(I:C) was observed to induce a Th1 bias in the SV40 Tag antibody response that led to successful antitumor responses not observed in animals treated only with poly(I:C) or SV40 Tag. These data have direct implications for immunotherapeutic strategies incorporating methods to elicit inflammatory reactions, particularly NK cell-driven lysis, against malignant cell types that express a tumor-specific antigen such as SV40 Tag.

Progressive disseminated histoplasmosis in systemic lupus erythematosus—an unusual presentation of acute tenosynovitis and a literature review

Progressive disseminated histoplasmosis is a disease where Histoplasma capsulatum affects multiple organs due to the inability of host cellular immunity to control the infection. Progressive disseminated histoplasmosis mainly involves the bone marrow, liver, and lungs. We report an unusual initial presentation of progressive disseminated histoplasmosis presenting as acute tenosynovitis in a systemic lupus erythematosus (SLE) patient. This report highlights the point that H. capsulatum may present as focal lesions and a high level of suspicion is needed to make the diagnosis, especially in SLE patients. We specifically reviewed reported cases of progressive disseminated histoplasmosis in SLE patients, and a review of the literature is presented.

CD4+ T Lymphocytes Are Critical Mediators of Tumor Immunity to Simian Virus 40 Large Tumor Antigen Induced by Vaccination with Plasmid DNA

ABSTRACT A mechanistic analysis of tumor immunity directed toward the viral oncoprotein simian virus 40 (SV40) large tumor antigen (Tag) has previously been described by our laboratory for scenarios of recombinant Tag immunization in BALB/c mice. In the present study, we performed a preliminary characterization of the immune components necessary for systemic tumor immunity induced upon immunization with plasmid DNA encoding SV40 Tag as a transgene (pCMV-Tag). Antibody responses to SV40 Tag were observed via indirect enzyme-linked immunosorbent assay following three intramuscular (i.m.) injections of pCMV-Tag and were typified by a mixed Th1/Th2 response. Complete tumor immunity within a murine model of pulmonary metastasis was achieved upon two i.m. injections of pCMV-Tag, as assessed by examination of tumor foci in mouse lungs, without a detectable antibody response to SV40 Tag. Induction-phase and effector-phase depletions of T cell subsets were performed in vivo via administration of depleting rat monoclonal antibodies, and these experiments demonstrated that CD4+ T lymphocytes are required in both phases of the adaptive immune response. Conversely, depletion of CD8+ T lymphocytes did not impair tumor immunity in either immune phase and resulted in the premature production of antibodies to SV40 Tag. Our findings are unique in that a dominant role could be ascribed to CD4+ T lymphocytes within a model of DNA vaccine-induced tumor immunity to Tag-expressing tumor cells. Additionally, our findings provide insight into the general mechanisms of vaccine-induced tumor immunity directed toward tumors bearing distinct tumor-associated antigens.

A Comparative Analysis of GeneXpert Real-Time PCR with Culture for the Detection of Methicillin-Resistant Staphylococcus aureus Colonization in Selected Hospital Admissions

Contact isolation of patients with methicillin-resistant Staphylococcus aureus (MRSA) reduces transmission to other patients and to health care workers. PCR technology can provide rapid detection of these patients. We tested the utility of using PCR for MRSA detection in patients with a history of MRSA infection or colonization or in a high risk group admitted to a general referral hospital. Nasal swabs from 342 patients were tested for MRSA on days one and three using the GeneXpert MRSA system. Swabs with a positive PCR result were cultured to identify staphylococcal species present in the nares. Fifty-six patients (38% of 147) with a history of MRSA colonization or infection were positive; forty-seven patients (24% of 195) in a high risk group were positive. Eighty-one percent of the patients with positive PCR swabs grew out MRSA on culture. Some cultures grew out only methicillin-sensitive Staphylococcus aureus, methicillin-sensitive, coagulase negative Staphylococcus, or methicillin-resistant, coagulase negative Staphylococcus. This study demonstrates that most patients at risk for MRSA colonization are not colonized and that microbiological surveillance using PCR technology can facilitate contact isolation decisions. Not all PCR positive results represent the presence of MRSA, and hospitals need to consider policies for additional evaluation of positive PCR tests.

Traditional culture methods fail to detect principle pathogens in necrotising soft tissue infection: a case report

OBJECTIVE Necrotising soft tissue infections (NSTIs) progress rapidly and mortality remains high, ranging from 10% to 30%, representing a significant challenge for health professionals. Early accurate diagnosis is crucial because timely and aggressive surgical intervention remains the number one indicator for a better clinical outcome. Understanding the microbial background of NSTIs would aid early diagnosis. PRESENTATION We present a case of NSTI, in a seemingly healthy adult male, originating from a tooth abscess. The NSTI progressed rapidly, and eventually covered the patients chest and abdominal skin and underlying soft tissue. RESULTS Traditional blood and tissue culture only found Group C Streptococcus where 16S sequencing detected abundant Prevotella spp., a more likely causal organisms of the NSTI. The use of antibiotics with the approriate anaerobe coverage, in combination with timely surgical intervention, contributed to the ultimate successful clinical outcome. Complete wound healing and successful graft was achieved within one month of diagnosis of the microbes present. CONCLUSION While surgical intervention remains the most important consideration in treatment of NSTI, correct identifcation of the microbial flora could also contribute to successful treatment.

The role of gamma interferon in DNA vaccine-induced tumor immunity targeting simian virus 40 large tumor antigen

The central role of CD4+ T lymphocytes in mediating DNA vaccine-induced tumor immunity against the viral oncoprotein simian virus 40 (SV40) large tumor antigen (Tag) has previously been described by our laboratory. In the present study, we extend our previous findings by examining the roles of IFN-γ and Th1-associated effector cells within the context of DNA immunization in a murine model of pulmonary metastasis. Immunization of BALB/c mice with plasmid DNA encoding SV40 Tag (pCMV-Tag) generated IFN-γ-secreting T lymphocytes that produced this cytokine upon in vitro stimulation with mKSA tumor cells. The role of IFN-γ as a mediator of protection against mKSA tumor development was assessed via in vivo IFN-γ neutralization, and these experiments demonstrated a requirement for this cytokine in the induction immune phase. Neutralization of IFN-γ was associated with a reduction in Th1 cytokine-producing CD4+ and CD8+ splenocytes, as assessed by flow cytometry analysis, and provided further evidence for the role of CD4+ T lymphocytes as drivers of the cellular immune response. Depletion of NK cells and CD8+ T lymphocytes demonstrated the expendability of these cell types individually, but showed a requirement for a resident cytotoxic cell population within the immune effector phase. Our findings demonstrate the importance of IFN-γ in the induction of protective immunity stimulated by pCMV-Tag DNA-based vaccine and help to clarify the general mechanisms by which DNA vaccines trigger immunity to tumor cells.