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Nanobodies (Nbs) are the smallest, functionally integrated unit that has a special importance in the researchers in the field of immunotherapy and biotechnology. These Nbs are derived from heavy chain antibodies only which are found in members of the Camelids, family (llama, camel, alpaca). this paper aimed to establish molecular library of genes encoded to Nbs specific to CD19,The immune response was evaluated by ELISA assay,which revealed a good immune response against the CD-19. Blood collection has performed at 71 days peripheral blood lymphocytes separated by density gradient centrifugation, cDNA synthesized from immunized lama RNA used as templet for amplify the CD19 -VHH encoding region with the nested polymerase reaction, the first reaction using primers amplification product are 700 bp were detected in 1% agarose gel corresponding to all VH domains of immunoglobulins : IgG2 and IgG3, then fragment at 400 bp was amplified in second PCR reaction, The second amplification product was cloned into vector pComb3Xss using E.coli Er2738 for transformation confirming the successful of cloning by colony PCR. [ABSTRACT FROM AUTHOR]

Aim: To analyze the neutralizing activity of antibodies against E1 region of hepatitis C virus (HCV). Specific polyclonal antibody was raised via immunization of New Zealand rabbits with a synthetic peptide that had been derived from the E1 region of HCV and was shown to be highly conserved among HCV published genotypes., Methods: Hyper-immune HCV E1 antibodies were incubated over night at 4 degree Celsius with serum samples positive for HCV RNA, with viral loads ranging from 615 to 3.2 million IU/ mL. Treated sera were incubated with HepG2 cells for 90 min. Blocking of viral binding and entry into cells by anti E1 antibody were tested by means of RT-PCR and flow cytometry., Results: Direct immunostaining using FITC conjugated E1 antibody followed by Flow cytometric analysis showed reduced mean fluorescence intensity in samples pre-incubated with E1 antibody compared with untreated samples. Furthermore, 13 out of 18 positive sera (72%) showed complete inhibition of infectivity as detected by RT-PCR., Conclusion: In house produced E1 antibody, blocks binding and entry of HCV virion infection to target cells suggesting the involvement of this epitope in virus binding and entry. Isolation of these antibodies that block virus attachment to human cells are useful as therapeutic reagents.