title: Newly exposed immunochemically cross-reactive epitopes in sperm-specific LDH after glucosylation and gossypol interaction.
abstract: OBJECTIVE
  In a previous study, mouse lactate dehydrogenase-C4 (LDH-C4) after chemical modifications with gossypol (Gossy-LDH-C4) and glucosylation with lactose (Glu-LDH-C4) was found to induce high immunological infertility in allogenic mice. In the present study, the characterization of antibodies and cross reactivity of the antisera produced against Gossy- and Glu-LDH-C4 with purified somatic isozymes are being reported.
  
  
  METHODS
  Allo-antisera generated in Balb/c mice (i.r. route) against one primary (50 microg) and two secondary doses (30 x 2 microg) in Al(OH)3 were tested for cross-reactivity by ELISA and antibody avidity using Scatchard plot and Sip's plot.
  
  
  RESULTS
  Results suggested that IgG against native LDH-C4 failed to recognize somatic isozyme, while antisera against chemically modified LDH-C4 consistently reacted with purified LDH from kidney and placenta. Scatchard plots and antibody saturation curves of native and complexed LDH supported the presence of heterogenous antibodies with a mean association constant (Ka) of the order of 10(6)-10(7) M(-1), whereas diversity of heterogeneity, defined by diversity constant (a), ranged between 0.89 and 1.23. In general, anti-Glu-LDH-C4 antiserum and native LDH-C4. reacted with higher Ka (low affinity) with a diversity constant of 0.89 compared with interaction between native LDH-C4 and it's antibodies.
  
  
  CONCLUSIONS
  It is concluded that LDH-C4 is not an immunochemically sperm-specific protein, in which crossreactive epitopes are hidden within its conformation. Due to the large intake of cotton seed (a source of gossypol) by cattle, its unrefined oil by humans in various parts of the world, and the prevelance of diabetic state all the world over, the present study warns of immunological consequences in situ following gossypol interaction and glucosylation of LDH and conformationally related proteins in circulation.
authors: Department of Biophysics, Panjab University, Chandigarh, India. rsic@chd.nic.in
authors: G S
authors: GS
authors: Gupta
authors: N
authors: N
authors: Syal
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D006031:Glycosylation; D006072:Gossypol; D007527:Isoenzymes / Q000276:immunology; D007770:L-Lactate Dehydrogenase / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D013094:Spermatozoa / Q000201:enzymology*
chemical_list: D018985:Epitopes, B-Lymphocyte; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D006072:Gossypol