The variable domain of heavy-chain antibody (VHH) has been developed widely in drug therapy, diagnosis, and research. Escherichia coli is the most popular expression system for VHH production, whereas low bioactivity occurs sometimes. Mammalian cells are one of the most ideal hosts for VHH expression at present. To improve the yield of VHH in Expi293F cells, we optimized the signal peptide (SP) and codons of VHH. Firstly, the fusion protein VHH1-Fc was used to screen SPs. The SP IFN-α2 showed the highest secretion as quantified by enzyme-linked immunosorbent assay (ELISA). Subsequently, codon optimization by improving GC3 and GC content doubled the yield of VHH1 and kept its binding activity to Senecavirus A (SVA). Finally, the mean yields of other 5 VHHs that fused with SP IFN-α2 and codon-optimized were over 191.6 mg/L, and these VHHs had high recovery and high purity in the culture supernatant. This study confirms that SP IFN-α2 and codon optimization could produce VHHs in Expi293F cells efficiently, which provides a reference for the large-scale production of VHHs.
Codon/genetics* ; Protein Sorting Signals/genetics* ; Escherichia coli/metabolism* ; Humans ; Recombinant Fusion Proteins/biosynthesis* ; Interferon-alpha/metabolism* ; Immunoglobulin Heavy Chains/immunology* ; Cell Line ; Immunoglobulin Variable Region/immunology*

OBJECTIVETo observe the clinical and biological characteristics of Non-IgM-secreting lymphoplasmacytic lymphoma (LPL) and draw the differences between non-IgM LPL and Waldenström macroglobulinemia (WM).

METHODSRecords of 13 patients with non-IgM LPL were retrospectively analyzed between January 2000 and December 2013. The cytogenetic aberrations were detected by fluorescence in situ hybridisation (FISH).

RESULTSIn the cohort, 7 males and 6 females with a median age of 63 years (range 43 to 74), two patients were IgA secreting, 6 with IgG secreting and 5 patients without monoclonal globulin. The major complaint at diagnosis included anemia associated symptom (53.8%), mucocutaneous hemorrhage and superficial lymphadenopathy (15.4%). Eight patients had B symptom at diagnosis. All of the 13 patients had bone marrow involvement and anemia, and 10 patients had 2 or 3 lineage cytopenia. In 5 patients with available immunophenotypic data, all expressed CD19, CD20, CD22 and CD25, but missed the expression of CD10, CD103 and CD38. Two cases had CD5 or sIgM positive alone. Another 2 patients were CD23 or CD11c positive and 3 patients were FMC7 positive. Cytogenetic aberrations had been detected by FISH in 7 patients, but only two (28.6%) patients had aberrations with del(6q).

CONCLUSIONThe clinical and biological characteristics had no significantly difference between non-IgM LPL and WM.

Adult ; Aged ; Antigens, CD ; Chromosome Aberrations ; Female ; Humans ; Immunoglobulin M ; In Situ Hybridization, Fluorescence ; Integrin alpha Chains ; Leukemia, Lymphocytic, Chronic, B-Cell ; Male ; Middle Aged ; Retrospective Studies ; Waldenstrom Macroglobulinemia

OBJECTIVETo study the frequency of major histocompatibility complex class I-related chain A (MICA) antibody in patients with end-stage renal disease (ESRD).

METHODSLuminex flow cytometry and beads loaded with 11 MICA antigens were used to identify the MICA antibody and evaluate the antibody specificity in 110 patients with ESRD.

RESULTSThe positivity rate of MICA antibody was 40% (12/30) in PRA-positive patients, significantly higher than the rate of 17.5% (14/80) in PRA-negative patients (chi(2)=6.120, P=0.013). MICA-specific antibodies against 10 of the 11 MICA antigens were detected in 26 MICA antibody-positive patients, and 26.92% of the MICA antibody-positive patients had antibodies with single-specificity and 73.08% had polyspecific antibodies. Three MICA antibody-positive patients with cadaveric kidney transplantation showed good function of the graft without acute rejection 2 months after the operation.

CONCLUSIONThe positivity rate of MICA antibody is significantly higher in PRA-positive patients, suggesting a strong correlation between MICA and PRA positivity. The MICA antibodies are polyspecific and probably consist of IgM and IgG. These data can be used as prospective data for these ESRD patients considering potential renal transplantation, and may facilitate further investigation of the association of MICA with renal transplantation.

Adult ; Antibodies ; blood ; immunology ; Female ; Histocompatibility Antigens Class I ; immunology ; Humans ; Immunoglobulin alpha-Chains ; blood ; immunology ; Kidney Failure, Chronic ; immunology ; surgery ; Kidney Transplantation ; Male ; Middle Aged ; Retrospective Studies