Sources/Clones
American Research Products (HIV1-1, HIV1-2), Biosource (LOHIV1-1), Dako (Kal-1) and Harlan SeraLab/Accurate (1HIVp24).
Fixation Preparation
Applicable to formalin-fixed, paraffin-embedded tissue sections. Pretreatment with proteolytic enzymes such as pronase improves immunoreactivity. May also be used for labeling cryostat sections and fixed-cell smears. Although the manufacturers provide working dilutions, optimization in individual laboratories is necessary. We have discovered that sections require a dual pretreatment with 0.5% trypsin (37 C, 15 min) followed by microwave treatment in citrate buffer.
Background
Kal-1 reacts with the HIV type 1 capsid protein p24 and its precursor p55 as demonstrated by immunohistochemistry, immunoprecipitation, ELISA and immunoblotting using lysates of purified virus and lysates of HIV type 1 infected cells (Daugharty et al, 1990). The antibody detects an epitope of the p24 protein, which is resistant to fixation and paraffin embedding (Kaluza et al, 1992). It does not crossreact with HIV type 2 or simian immunodeficiency virus (SIV), as shown by immunoblotting. During the phase of persistent generalized lymphadenopathy and subsequent stages of disease leading to the development of AIDS, follicular dendritic cells forming the framework of lymphoid follicles degenerate (Tenner-Racz et al, 1986). The expression of HIV-1 proteins by follicular dendritic cells (FDC) in germinal centers in situ and the presence of HIV-1 mRNA+ cells in germinal follicles suggest that FDC are infected and able to produce HIV-1 (Parmentier et al, 1990). Such infection may contribute significantly to the destruction of the FDC network during the lymphadenopathy phase after HIV-1 infection. Kal-1 reacts with the p24 protein in cells infected with HIV type 1, i.e. lymphocytes, monocytes and macrophages, Langerhans cells of the skin, follicular dendritic cells and brain cells of monocyte-macrophage or microglia lineage.
On formalin-fixed, paraffin-embedded tissue, Kal-1 antibody produces a positive immunoreaction of HIV-infected dendritic reticulum cells in the germinal centers of lymph nodes. The dendritic processes are highlighted, producing the typical network pattern within germinal centers. Occasional positive mononuclear cells and lymphocytes may be observed in the interfollicular areas of the lymph node. However, only immunopositivity confined to the follicular dendritic cells in lymph nodes should be considered as specific.
Comments
Interpretation of a positive lymph node biopsy with this antibody should always be confirmed with a serological assay or Western blot. In some countries an informed consent is required from the patient before testing for HIV status. Hence, histopathologists should be cautious in the reporting of p24 + lymph node biopsies.
References
•Daugharty H, Long EG, Swisher BC et al 1990. Comparative study with in situ hybridization and immunocytochemistry in detection of HIV-1 in formalin-fixed paraffin-embedded cell cultures. Journal of Clinical Laboratory Analysis 4:283-288.
•Kaluza G, Willems WR, Lohmeyer J et al 1992. A monoclonal antibody that recognizes a formalin-resistant formalin-resistant epitope on the p24 core protein of HIV-1. Pathology Research and Practice; 188:91-96.
•Parmentier HK, Van Wicken D, Sie-Go DM et al 1990. HIV-1 infection and virus production in follicular dendritic cells in lymph nodes. A case report with analysis of isolated follicular dendritic cells. American Journal of Pathology; 137:247-251.
•Tenner-Racz K, Racz P, Bofill M et al 1986. HTLV-III/LAV viral antigens in lymph nodes of homosexual men with persistent generalized lymphadenopathy and AIDS. Journal of Pathology; 123: 9-15.
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
American Research Products (HIV1-1, HIV1-2), Biosource (LOHIV1-1), Dako (Kal-1) and Harlan SeraLab/Accurate (1HIVp24).
Fixation Preparation
Applicable to formalin-fixed, paraffin-embedded tissue sections. Pretreatment with proteolytic enzymes such as pronase improves immunoreactivity. May also be used for labeling cryostat sections and fixed-cell smears. Although the manufacturers provide working dilutions, optimization in individual laboratories is necessary. We have discovered that sections require a dual pretreatment with 0.5% trypsin (37 C, 15 min) followed by microwave treatment in citrate buffer.
Background
Kal-1 reacts with the HIV type 1 capsid protein p24 and its precursor p55 as demonstrated by immunohistochemistry, immunoprecipitation, ELISA and immunoblotting using lysates of purified virus and lysates of HIV type 1 infected cells (Daugharty et al, 1990). The antibody detects an epitope of the p24 protein, which is resistant to fixation and paraffin embedding (Kaluza et al, 1992). It does not crossreact with HIV type 2 or simian immunodeficiency virus (SIV), as shown by immunoblotting. During the phase of persistent generalized lymphadenopathy and subsequent stages of disease leading to the development of AIDS, follicular dendritic cells forming the framework of lymphoid follicles degenerate (Tenner-Racz et al, 1986). The expression of HIV-1 proteins by follicular dendritic cells (FDC) in germinal centers in situ and the presence of HIV-1 mRNA+ cells in germinal follicles suggest that FDC are infected and able to produce HIV-1 (Parmentier et al, 1990). Such infection may contribute significantly to the destruction of the FDC network during the lymphadenopathy phase after HIV-1 infection. Kal-1 reacts with the p24 protein in cells infected with HIV type 1, i.e. lymphocytes, monocytes and macrophages, Langerhans cells of the skin, follicular dendritic cells and brain cells of monocyte-macrophage or microglia lineage.
On formalin-fixed, paraffin-embedded tissue, Kal-1 antibody produces a positive immunoreaction of HIV-infected dendritic reticulum cells in the germinal centers of lymph nodes. The dendritic processes are highlighted, producing the typical network pattern within germinal centers. Occasional positive mononuclear cells and lymphocytes may be observed in the interfollicular areas of the lymph node. However, only immunopositivity confined to the follicular dendritic cells in lymph nodes should be considered as specific.
Comments
Interpretation of a positive lymph node biopsy with this antibody should always be confirmed with a serological assay or Western blot. In some countries an informed consent is required from the patient before testing for HIV status. Hence, histopathologists should be cautious in the reporting of p24 + lymph node biopsies.
References
•Daugharty H, Long EG, Swisher BC et al 1990. Comparative study with in situ hybridization and immunocytochemistry in detection of HIV-1 in formalin-fixed paraffin-embedded cell cultures. Journal of Clinical Laboratory Analysis 4:283-288.
•Kaluza G, Willems WR, Lohmeyer J et al 1992. A monoclonal antibody that recognizes a formalin-resistant formalin-resistant epitope on the p24 core protein of HIV-1. Pathology Research and Practice; 188:91-96.
•Parmentier HK, Van Wicken D, Sie-Go DM et al 1990. HIV-1 infection and virus production in follicular dendritic cells in lymph nodes. A case report with analysis of isolated follicular dendritic cells. American Journal of Pathology; 137:247-251.
•Tenner-Racz K, Racz P, Bofill M et al 1986. HTLV-III/LAV viral antigens in lymph nodes of homosexual men with persistent generalized lymphadenopathy and AIDS. Journal of Pathology; 123: 9-15.
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
