ABSTRACT
Introduction: Osteochondroma is the most common benign bone tumor (20-50%). It is located predominantly in the metaphysis of the long bones, and much less frequently, the proximal femur and acetabulum. Osteochondroma can eventually lead to hip osteoarthritis and limit patients' functional activities. Determining optimal treatment can be difficult due to the high risk of avascular necrosis in surgical resections. Case Report: A 44-year-old male from Sabinas Coahuila, Mexico, a priest by profession, who presents for consultation with right inguinal pain of 18 months' duration. The patient had been treated conservatively with rest, non-steroidal anti-inflammatory drugs, and physical therapy without showing improvement in his symptoms. The anteroposterior radiograph of the pelvis and axial tomography showed an oval bone excrescence with well-defined margins in the acetabular and intra-articular region of the hip, which caused a decrease in joint space but without soft tissue infiltration. Tumor resection and total hip replacement were the treatment options. The histopathological study concluded an osteochondroma. After 25 months of post-operative follow-up, radiographic studies show no evidence of lesion recurrence. The functional improvement is 98 points on the Harris scale; the patient typically performs his daily living and work activities. Conclusion: Treating intra-articular osteochondroma of the hip can be challenging for the orthopedic surgeon. For osteochondroma resulting in secondary osteoarthrosis of the hip joint, total hip replacement should be considered an effective method to restore function and assist in returning the patient to previous activities. Thorough pre-operative planning is mandatory to prevent intra- or immediate post-operative risk.
ABSTRACT
BACKGROUND: The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on. OBJECTIVE: Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness. CONCLUSION: The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.
Subject(s)
Carrier Proteins , T-Lymphocytes , Epitopes , Cell MembraneABSTRACT
BACKGROUND: An antigen is a small foreign substance, such as a microorganism structural protein, that may trigger an immune response once inside the body. Antigens are preferentially used rather than completely attenuated microorganisms to develop safe vaccines. Unfortunately, not all antigens are able to induce an immune response. Thus, new adjuvants to enhance the antigen's ability to stimulate immunity must be developed. OBJECTIVES: Therefore, this work aimed to evaluate the molecular-structure adjuvant activity of tannic acid (TA) coupled to a protein antigen in Balb/c mice. METHODS: Bovine serum albumin (BSA) was used as an antigen. The coupling of BSA and TA was mediated by carbodiimide crosslinking, and verified by SDS-PAGE. Forty-two Balb/c mice were divided into seven groups, including two controls without antigen, an antigen control, an adjuvant control, and two treatment groups. An additional group was used for macrophages isolation. A 30-day scheme was used to immunize the mice. The analysis of humoral immunity included immunoglobulin quantification, isotyping and antigen-antibody precipitation. The analysis of cell-mediated immunity included the quantification of nitric oxide from peritoneal macrophages and splenocytes' proliferation assay after treatment stimulation. RESULTS: No differences were found in the antibodies' concentration or isotypes induced with the conjugate or the pure BSA. However, an immunogenicity improvement (p < 0.05) was observed through the specific anti-BSA antibody titers in mice immunized with the conjugate. Besides, macrophage activation (p < 0.05) was detected when stimulated with the treatments containing TA. CONCLUSION: Tannic acid exhibited macrophages' activation properties. Moreover, when TA was incorporated into the structure of a protein antigen, such as BSA, an antibody specificity enhancement was observed. This was a consequence of antigen processing by activated antigen-presenting cells. These results showed the use of tannic acid as a novel candidate for vaccine molecular-structure adjuvant.