High affinity nanobodies against human epidermal growth factor receptor selected on cells by E. coli display

Most therapeutic antibodies (Abs) target cell surface proteins on tumor and immune cells. Cloning of Ab gene libraries in E. coli and their display on bacteriophages is commonly used to select novel therapeutic Abs binding target antigens, either purified or expressed on cells. However, the sticky nature of bacteriophages renders phage display selections on cells challenging. We previously reported an E. coli display system for expression of VHHs (i.e., nanobodies, Nbs) on the surface of bacteria and selection of high-affinity clones by magnetic cell sorting (MACS). Here, we demonstrate that E. coli display is also an attractive method for isolation of Nbs against cell surface antigens, such as the epidermal growth factor receptor (EGFR), upon direct selection and screening of Ab libraries on live cells. We employ a whole cell-based strategy using a VHH library obtained by immunization with human tumor cells over-expressing EGFR (i.e., A431), and selection of bacterial clones bound to murine fibroblast NIH-3T3 cells transfected with human EGFR, after depletion of non-specific clones on untransfected cells. This strategy resulted in the isolation of high-affinity Nbs binding distinct epitopes of EGFR, including Nbs competing with the ligand, EGF, as characterized by flow cytometry of bacteria displaying the Nbs and binding assays with purified Nbs using surface plasmon resonance. Hence, our study demonstrates that E. coli display of VHH libraries and selection on cells enables efficient isolation and characterization of high-affinity Nbs against cell surface antigens.

Acute generalized exanthematous pustulosis associated with pseudoephedrine

Acute generalized exanthematous pustulosis (AGEP) is an uncommon skin disorder most often caused by drugs. Few adverse reactions to sympathomimetic drugs have been reported, despite their extensive use. Although the aetiology of AGEP remains uncertain, recent data have reported involvement of drug-specific T cells and interleukin (IL)-8 production. We characterized an adverse reaction to pseudoephedrine both clinically and immunologically. Histological analysis of skin biopsies confirmed the clinical entity as AGEP, while epicutaneous tests confirmed the specificity of the reaction to the drug. Moreover, immunohistochemical studies showed a mononuclear infiltrate consisting of activated memory T cells in addition to polymorphonuclear cells. Reverse transcription-polymerase chain reaction revealed an increased expression of IL-8 in AGEP-affected skin.

Increasing incidence of ovarian pregnancy

This paper presents the results of a review of seven ovarian pregnancies occurring during an 11 year period (1976-1986). The prevalence of the disease is higher than that expected either for the number of deliveries or for all ectopic pregnancies. The presence of etiological factors such as pelvic inflammatory disease, previous abdominal surgery, endometriosis or use of IUD, is considered. Four of these cases presented in actual users of IUD and one in an infertile woman previously diagnosed of endometriosis. The clinical pattern was similar to that recorded for tubal ectopic pregnancies. The role of IUDs and other risk factors in the apparent increase in the number of ectopic pregnancies detected is discussed. Measures to increase accuracy in the detection of early ovarian pregnancies are proposed.