Development, Screening, and Validation of Camelid-Derived Nanobodies for Neuroscience Research

Nanobodies (nAbs) are recombinant antigen-binding variable domain fragments obtained from heavy-chain-only immunoglobulins. Among mammals, these are unique to camelids (camels, llamas, alpacas, etc.). Nanobodies are of great use in biomedical research due to their efficient folding and stability under a variety of conditions, as well as their small size. The latter characteristic is particularly important for nAbs used as immunolabeling reagents, since this can improve penetration of cell and tissue samples compared to conventional antibodies, and also reduce the gap distance between signal and target, thereby improving imaging resolution. In addition, their recombinant nature allows for unambiguous definition and permanent archiving in the form of DNA sequence, enhanced distribution in the form of sequences or plasmids, and easy and inexpensive production using well-established bacterial expression systems, such as the IPTG induction method described here. This article will review the basic workflow and process for developing, screening, and validating novel nAbs against neuronal target proteins. The protocols described make use of the most common nAb development method, wherein an immune repertoire from an immunized llama is screened via phage display technology. Selected nAbs can then be taken through validation assays for use as immunolabels or as intrabodies in neurons. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Total RNA isolation from camelid leukocytes Basic Protocol 2: First-strand cDNA synthesis; VH H and VH repertoire PCR Basic Protocol 3: Preparation of the phage display library Basic Protocol 4: Panning of the phage display library Basic Protocol 5: Small-scale nAb expression Basic Protocol 6: Sequence analysis of selected nAb clones Basic Protocol 7: Nanobody validation as immunolabels Basic Protocol 8: Generation of nAb-pEGFP mammalian expression constructs Basic Protocol 9: Nanobody validation as intrabodies Support Protocol 1: ELISA for llama serum testing, phage titer, and screening of selected clones Support Protocol 2: Amplification of helper phage stock Support Protocol 3: nAb expression in amber suppressor E. coli bacterial strains.

Graphene Oxide Nanosheets Modified with Single-Domain Antibodies for Rapid and Efficient Capture of Cells

Peripheral blood can provide valuable information on an individual's immune status. Cell-based assays typically target leukocytes and their products. Characterization of leukocytes from whole blood requires their separation from the far more numerous red blood cells.1 Current methods to classify leukocytes, such as recovery on antibody-coated beads or fluorescence-activated cell sorting require long sample preparation times and relatively large sample volumes.2 A simple method that enables the characterization of cells from a small peripheral whole blood sample could overcome limitations of current analytical techniques. We describe the development of a simple graphene oxide surface coated with single-domain antibody fragments. This format allows quick and efficient capture of distinct WBC subpopulations from small samples (∼30 μL) of whole blood in a geometry that does not require any specialized equipment such as cell sorters or microfluidic devices.

A prognostic algorithm including a modified version of MD Anderson Cancer Center (MDACC) score predicts time to first treatment of patients with clinical monoclonal lymphocytosis (cMBL)/Rai stage 0 chronic lymphocytic leukemia (CLL)

We propose an algorithm based on a slightly modified version of MD Anderson Cancer Center (MDACC) score (i.e., mutational status of IgVH, LDH, presence of high-risk FISH abnormalities), β2-microglobulin and separation of clinical monoclonal B-cell lymphocytosis (cMBL) from chronic lymphocytic leukemia (CLL) to predict time to first treatment (TTFT) of a prospective multicentre cohort including 83 cMBL and 136 CLL Rai stage 0 patients. Patients with MDACC score point ≥38, at any level of β2-microglobulin and irrespective of whether they fulfilled 2008 International Workshop on CLL (IWCLL) criteria for CLL Rai stage 0 or cMBL, experienced the worst clinical outcome (5-year TTFT, 24%) and formed the high-risk group. In contrast, subjects with a diagnosis of cMBL, MDACC score point <38 and β2-microglobulin ≤ UNL had the best clinical outcome (5-year TTFT, 100%) and constituted the low-risk group. The intermediate group included patients in Rai stage 0, MDACC score point <38, and any level of β2-microglobulin, and patients with cMBL, MDACC score point <38, and β2-microglobulin ≥ UNL. Cases showing these features can be grouped together to form the intermediate-risk group (5-year TTFT, 65%). Although the separation between cMBL and Rai stage 0, as proposed by the 2008 IWCLL guidelines, has clinical implications, the model we propose may help to classify patients with cMBL and Rai stage 0 into more precise subgroups suggesting that a prognostic separation of these entities based solely on clonal B-cell threshold may be unsatisfactory.

Generation and isolation of target-specific single-domain antibodies from shark immune repertoires

The drive to exploit novel targets and biological pathways has lead to the expansion of classical antibody research into innovative fragment adaptations and novel scaffolds. The hope being that alternative or cryptic epitopes may be targeted, tissue inaccessibility may be overcome, and easier engineering options will facilitate multivalent, multi-targeting approaches. To this end, we have been isolating shark single domains to gain a greater understanding of their potential as therapeutic agents. Their unique shape, small size, inherent stability, and simple molecular architecture make them attractive candidates from a drug discovery perspective. Here we describe protocols to capture the immune repertoire of an immunized shark species and to build and select via phage-display target-specific IgNAR variable domains (VNARs).