[Relationship between M-Protein of Multiple Myeloma and False Positive Syphilis Serological Results].

BACKGROUND: The false positive in conventional syphilis serological test was found in patients with multiple myeloma (MM). OBJECTIVE: To investigate the relationship between the M-protein of patients with MM and the false positive in conventional syphilis serologic test. METHODS: The M-protein of 68 MM cases was typed with immunofixation electrophoresis and 68 cases of MM were screened with non-specific and specific syphilis serologic tests, then the samples with syphilic serological positive were chosen and confirmed with immonobloting test, finally the relationship between M protein of MM and the false positive of syphilis serological test were analysed. RESULTS: Four out of 68 cases showed the positive in syphilis serological test and further were confimed to be false positive by immunoblotting test, the false positive rate was nearly 6%. The M-protein of MM patients in our hospital mostly possessed IgG, κ type, followed by IgA, κ type, light chain κ type. In general, κ : λ = 2.4 : 1. Among samples of 4 cases with syphilis serological positive 2 cases were of IgG and κ type, 1 case was of IgG, λ type, another 1 case was IgA, κ type. CONCLUSION: The M-protein of IgG and IgA types in MM patients results in syphilis serological false positive reaction. The clinicians and laboratorial technicians should pay a great attention to screen the MM patients for the false positive syphilis serological test so as to avoid the misdiagnosis and subsequent embarassment.

[Preparation and selection of the monoclonal antibody used for kits to detect BNP32 which was applied to clinical research].

AIM: To prepare the monoclonal antibody (mAb) used for kits to detect the BNP32 antigen by means of double-antibody sandwich ELISA assay. Comparasion differences on detection BNP between double-antibody sandwich ELISA and Roche ECL. METHODS: BALB/c mice were immunized with purified recombinant BNP32 protein and by routine hybridoma technique, Then comparasion differences on detection BNP between double-antibody sandwich ELISA and Roche ECL. RESULTS: 16 hybridoma cell lines secreting potent mAb against BNP32 were obtained. The subtype of these 16 mAb were found to be IgG1, IgG2a and IgM, then their cross-blocking properties were analyzed, when they reacted with the BNP32 protein in direct ELISA in order to offer the valuable data for selecting feasible pair of mAb in the detection of the BNP32 antigen. All the mAbs were used for the detection of BNP32 by double-antibody sandwich ELISA. In addition, the mAbs were purified and HRP-labelled in advance. Finally, we had successfully screened a pair of mAbs, which exhibited a sensitivity of 20 ng/L for the detection of BNP32 antigen. The two detection methods have very good consistency (kappa=0.828>0.75)between double-antibody sandwich ELISA and Roche ECL. There was no statistics significance on differences between these two methods(P>0.05). CONCLUSION: It is evident that this pair of mAb shows excellent detection of BNP32. The double-antibody sandwich ELISA can be good apply to detect BNP level in clinical congestive heart failure patients.

[Preparation and application of anti-serum against mouse Foxp3].

AIM: To prepare the high titer and specific anti-serum against mouse Foxp3 and then use them to identify Foxp3 expression in normal mouse tissues. METHODS: The Foxp3 fragment was amplified by polymerase chain reactions(PCR) and cloned into the prokaryotic expression vector pGEX-6p-2. The recombinant plasmid pGEX-6p-2/Foxp3 was transformed into E.coli BL21(DE3) to be expressed. The expressed fusion protein GST-Foxp3 was analyzed by SDS-PAGE and Western blot. The polyclonal clanti-serum was obtained by immunizing New Zealand rabbits with the purified fusion protein as antigen. The Foxp3 expression in normal mouse tissues was detected by Western blot with the anti-serum. RESULTS: The expressed products were analyzed by SDS-PAGE and Western blot. The results showed that the molecular weight of the expressed protein was about 45 000. The titer of the anti-serum was above 1:12 800. We observed that the anti-serum could recognize Foxp3 protein expressed in NIH3T3 cells by immunoblotting. Western blot results showed that the Foxp3 protein was expressed highly in spleen, thymus and lymph nodes, less expressed in stomach, but not expressed in skeletal muscle and adipose tissue. CONCLUSION: High titer antiserum against mouse Foxp3 is produced and can be used to identify the Foxp3 expression in normal mouse tissues.