ISSN 2398-2969      

Immunotherapy

Clapis

Introduction

  • Treatment of disease by inducing, enhancing or suppressing the immune response.
  • Used for certain types of cancer.
  • Agents such as acemannan (an Aloe vera extract), interferon and retinoids have been used with apparent success in rabbits.
  • Other immunotherapy agents used in other species or humans include: hyperimmune serum, allergen-specific immunotherapy, cancer vaccines, adoptive cellular therapy, tumor microenvironment modification, checkpoint molecule targeted immunotherapies, viral-vectored cytokine delivery, bacterial delivered therapeutics.
  • Corticosteroids, cyclophosphamide and cyclosporine can regulate the immune response and some of them are used in the treatment of cancer; however, these drugs are not usually included under the term “immunotherapy”.
  • Many drugs and substances have been used experimentally in rabbits for human research, but there are few reports of their use in clinical medicine of companion rabbits.

Uses

Advantages

  • Immunotherapy with Aloe vera, interferon or retinoids is usually a therapy with few and mild side effects.

Disadvantages

  • Immunotherapy by itself is rarely curative and needs the application of other agents to properly treat cancer Cancer therapy overview.

Aloe vera (and extracts of Aloe vera such as acemannan)

  • Aloe vera is an inexpensive and readily available herb.
  • It is a trigger for cell proliferation, differentiation, mineralization and dentin formation in rabbits and other species, so Aloe vera gel can be used in rabbits topically in cases of avulsed or damaged teeth, when regrowth of the tooth is desirable.
  • Aloe vera also has antioxidant, antimicrobial and immunomodulatory activity. It stimulates cellular and humoral immune responses when given orally in rabbits.
  • The use of Aloe vera orally also has beneficial properties in disk disease and skin disease.
  • The use of topical Aloe vera facilitates the healing of wounds. In combination with systemic pentoxifylline, it is useful to treat frostbite.
  • Aloe vera has also been used in other species to treat neoplasia, as acemannan causes macrophage activation, leading to release of tumor necrosis factor, interleukin-1 and interferon. It can be used intratumorally or systemically (in combination with surgical debulking).

 Corticosteroids

  • Glucocorticosteroids Therapeutics: glucocorticoids are immunosuppressive agents that can be used to treat a variety of conditions.
  • Glucocorticoids decrease circulating levels of T-lymphocytes; inhibit lymphokines; inhibit neutrophil, macrophage, and monocyte migration; reduce production of interferon; inhibit phagocytosis and chemotaxis; and diminish intracellular killing.
  • Specific acquired immunity is affected less than nonspecific immune responses.
  • Adverse effects are generally associated with long-term administration.
  • In rabbits, glucocorticoids have been used to treat cancer, particularly lymphoproliferative neoplasia. It can be used alone (palliative) or in combination with other therapies (palliative or curative). It may slow down the progression of the disease.
  • It is an inexpensive therapy.

Cyclophosphamide

  • Cyclophosphamide is an alkylating agent used as both an antineoplastic agent and an immunosuppressant.
  • As an antineoplastic, it is used in combination with other agents to treat lymphomas, leukemias, carcinomas and sarcomas.
  • Cyclophosphamide has marked immunosuppressive activity, and decreases both white cells and antibody production.
  • Cyclophosphamide is rarely used in rabbits, but protocols have been described for the treatment of lymphoma:
    • 50 mg/m2 PO q24h 2-3 days per week or 100-200 mg/m2 IV weekly to every 3 weeks (often combined with doxorubicin).
    • Protocols with lower dosage have also been described (5-6 mg/m2 IV q21d).
  • Adverse effects include: bone marrow suppression, gastrointestinal effects and hemorrhagic cystitis.

Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Dow S (2020) A role for dogs in advancing cancer immunotherapy research. Front Immunol 10, 2935 PubMed.
  • Sholehvar F, Mehrabani D, Yaghmaei P et al (2016) The effect of Aloe vera gel on viability of dental pulp stem cells. Dental Traum 32 (5), 390-396 PubMed.
  • Vahedi G, Taghavi M, Maleki A K et al (2011) The effect of Aloe vera extract on humoral and cellular immune response in rabbit. Afr J Biotech 10 (26), 5225-5228.

Other sources of information

  • Meredith A & Lord B (2014) BSAVA Manual of Rabbit Medicine. BSAVA, UK. pp 328.

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