Authors: Brittany L. Bunch, Krithika N. Kodumudi, Ellen Scott, Jennifer Morse, Amy Mackay Weber, Anders E. Berglund, Shari Pilon-Thomas & Joseph Markowitz
Emm55 is a bacterial gene derived from Streptococcus pyogenes (S. pyogenes) that was cloned into a plasmid DNA vaccine (pAc/emm55). In this study, we investigated the anti-tumor efficacy of pAc/emm55 in a B16 murine melanoma model. Intralesional (IL) injections of pAc/emm55 significantly delayed tumor growth compared to the pAc/Empty group. There was a significant increase in the CD8+ T cells infiltrating into the tumors after pAc/emm55 treatment compared to the control group. In addition, we observed that IL injection of pAc/emm55 increased antigen-specific T cell infiltration into tumors. Depletion of CD4+ or CD8+ T cells abrogated the anti-tumor effect of pAc/emm55. Combination treatment of IL injection of pAc/emm55 with anti-PD-1 antibody significantly delayed tumor growth compared to either monotherapy. pAc/emm55 treatment combined with PD-1 blockade enhanced anti-tumor immune response and improved systemic anti-tumor immunity. Together, these strategies may lead to improvements in the treatment of patients with melanoma.
Authors: Patricia D. Lawman, and Michael J. P. Lawman
Cancer immunotherapies, which includes cancer vaccines, are novel therapeutic modalities being added to the armamentarium for cancer management/treatments that are finally becoming available to cancer patients around the world. In contrast to chemo and radiotherapies, cancer vaccines are not normally associated with severe side effects, and unlike chemo and radiotherapies which directly kill the tumor cells and normal rapidly dividing cells in the body, cancer vaccines and other immunotherapies exert their effect by stimulating the body’s immune system to focus on the cancer cells alone, remove them and consequently reduce the severity of the disease, generally without toxicity. Given these characteristics, cancer vaccines offer cancer patients a more focused and gentler means of cancer treatment that is far less detrimental to their bodies and is cognizant of the patient’s wish for a better quality of life.
Authors: Vijayakumar K. Ramiya, Maya M. Jerald, Patricia D. Lawman, and Michael J. P. Lawman
Cancer immunotherapies are emerging as promising treatment modalities in the management of the disease. As a result, cancer vaccines are considered to be immensely crucial in preventing recurrence, a well- known nemesis in cancer patients because they have the potential to activate memory antitumor immunity. Due to poor antigenicity and self-tolerance, most tumor antigens require interventional vaccine therapies to provide an adequate “danger” signal to the immune system in order to activate a robust, clinically meaningful antitumor immunity. It has been postulated that this requirement may be achieved by providing bacterial and/or viral immunogens to prime this type of immune response. Briefly, we provide here a method of transfecting whole tumor cells with plasmid DNA encoding an immunogenic bacterial protein such as Emm55, which was derived from Streptococcus pyogenes (S. pyogenes). Subsequent inactivation of the transfected cells by irradiation (100 Gray) prevents replication.
This type of whole-cell vaccine, e.g., ImmuneFx, has demonstrated activity in a murine neuroblastoma model, in canine lymphoma patients with naturally occurring disease, and in many cancer types in companion animals. The protocols described in this chapter provide the necessary materials and methodologies to manufacture such a vaccine.
Authors: Elizabeth L. Brown DVM, Vijayakumar K. Ramiya PhD, Cara A. Wright DVM, Maya M. Jerald DVM, Angela D. Via PSM, Venkata N. Kuppala PhD, William S. Hazell, Patricia D. Lawman PhD, Michael J. Lawman PhD
A 19-year-old castrated male Arab/Quarter horse presented with an extensive history of cutaneous metastatic melanoma. Over a period of 8 months, a total of 8 doses of plasmid DNA vaccine expressing the Streptococcus pyogenes emm55 gene (pAc/emm55) were administered intratumorally at 300mg/dose via a needless injector. Upon completion of the vaccination protocol, the size of the injected lesions, on average, were reduced by 40.3% from the initial size measurements. Lesions that were not injected were reduced by 47.6%.
The overall reduction in total tumor burden was 42.3%. Tumor regression was also associated with the augmentation of antimelanoma IgG antibody response, thus implying that an induction of an effective antimelanoma response would be of great advantage in the
management of equine melanoma.
(C)2013 Elsevier Inc. All rights reserved
Authors: Michael Lawman, Shabnam Eidizadeh, Christopher Selmon, Curtis Kane, Laura Xigacos, Laura Kaufman, Neil Shaw, Pat Lawman
ImmuneFx is an immunotherapy based on tumor cells transfected with the gene encoding Emm55, a Streptococcus pyogenes serotyping antigen. The ImmuneFx cancer vaccine was tested in 7 canine lymphoma patients with naturally-occurring disease. Humoral immunity was assessed by both PAGE Western blot analysis and quantitative Western dot-blot immunoassays. Cell-mediated immunity to autologous and allogeneic tumor cells was assessed by CTL assays. Clinical response was assessed by standard measurement criteria, and internal lesions were monitored by ultrasound. All dogs exhibited no adverse side-effects from the vaccine; developed an antibody response to the ImmuneFx priming antigen; and developed an antibody response to multiple autologous tumor cell antigens and tumor cell antigens from all other canine breeds on the trial. Furthermore, all dogs showed significant CD8+-mediated cellular cytotoxicity specific to their own tumor cells but also demonstrated the presence of CD4+ effector cells in the expanded lymphocyte population. The cytotoxic activity against the allogeneic target was attributable to the activity of CD4+ effector cells. While all dogs showed positive clinical response to varying degrees, a therapeutically significant anti-tumor response was elicited against the slower growing indolent lymphoma. In this one dog (Golden Retriever), a pre-study abdominal ultrasound revealed mesenteric lymphadenopathy and that her spleen was coarse in echotexture and echogenicity with ill-defined nodular lesions. After 12 vaccine doses over 5 months, a post-vaccination ultrasound was unremarkable, with no abnormalities noted in the spleen and no mesenteric lymphadenopathy in evidence. Continued clinical evaluation reports reveal that no new lesions have been observed from the onset of the vaccine regimen, and all previous lesions have regressed. These results support the safety and anti-tumor response of the ImmuneFx cancer vaccine in dogs with naturally-occurring lymphoma and suggest that the same response would be similar in other veterinary cancers.