1. What is Nanobody?

Nanobody was first proposed and reported in Nature by Belgian scientists in 1993. The traditional antibody molecule (IgG) is composed of two identical heavy chains and light chains. The light chain of antibody molecule contains one VL region and one CL region, while the heavy chain has one VH region and three CH regions (CH1, CH2 and CH3).

Alpaca only has heavy chain antibody but lacks light chain, which is composed of four HC's and two VH's. Among them, VHH region is also called nano antibody or single domain antibody (sdAb) and Nanobody (Nb). It’s crystal is 2.5nm, 4nm in length and only 15KDa in molecular weight. Nano-antibodies are mainly used in biomedical research and development (genetic engineering drug research and development, ADC drug research and development); Used for clinical diagnosis in vitro (colloidal gold method, enzyme-linked immunosorbent assay, electrochemiluminescence method); It is used in basic research fields such as tumor research and immunology. At present, the development of CAR-T therapeutic antibody has attracted more and more researchers' attention.

2. Advantages and Disadvantages of Nanobody

2.1 Advantages of Nanobody

(1) stability at high temperature and pH;

(2)VHH can recognize antigen sites that are not usually recognized by conventional antibodies;

(3) Their small molecular fragments are helpful for rapid tissue penetration and labeling applications, including crossing the blood-brain barrier;

(4) Cost-saving substitutes for mass production.

2.2 Disadvantages of Nanobody

Nanobody (VHH antibody) has a small molecular weight of about 15kDa, which is equivalent to the variable region of the heavy chain or light chain of traditional IgG antibody. Therefore, the secondary antibody against VHH antibody is not universally applicable, and it is necessary to co-express the VHH fusion Fc fragment to solve the problem of secondary antibody recognition (KMD Bioscience provides a variety of anti-alpaca secondary antibodies, which can be used to detect the titer of immune serum, cat. #: SPAB01, SPAB03).

3. Application of Nanobody (VHH antibody)

Based on the special structure and properties of Nanobody, it is favored by people in the field of CAR-T therapeutic antibody development.

CAR-T therapy is a new type of targeted therapy for tumor, that is, chimeric antigen receptor T cell immunotherapy. By means of genetic engineering technology, activated T cells are equipped with a positioning navigation device CAR (tumor chimeric antigen receptor) to turn T cells into "super soldiers", that is, CAR-T cells. With its positioning navigation device CAR, tumor cells in vivo can be accurately and specifically identified and eliminated.

4. KMD Bioscience Provides Customers with High-Quality Camelid Nanobody Development Services

KMD Bioscience can provide a variety of camel-derived Nanobody development services, including alpacas, llamas, camelus, etc. Based on the phage display technology platform, KMD Bioscience can provide major experimental links including antigen design, alpaca immunity, library construction and screening, and activity function identification, and provide alpaca VHH antibodies with high specificity and high affinity for scientists around the world. 

5. KMD Bioscience Provides Customers with an Introduction to the Whole Process of Camelid Antibody Development

It mainly includes the following steps: alpaca immunization, phage library construction, antibody library screening, antibody expression and function identification. The detailed process is as follows:

5.1 Alpaca Immunization

KMD Bioscience provides healthy adult alpacas (28-36 months old) for immunization, and high-quality libraries and monoclonal antibody cell lines can be obtained in about 16-20 weeks, and complete experimental process records and immune dynamic videos can be delivered. According to the antigen type of customers, KMD Bioscience will make specific immune antigen generation plans and immunization plans.

5.1.1 Generation of Antigen: The customer provides the antigen, the dosage of Freund's adjuvant is 1ml, and the antigen and adjuvant are mixed in a ratio of 1:1 for immunization.

5.1.2 Alpaca Immunization: the alpaca was immunized for 5 times with an interval of 20 days, and the alpaca was injected in the neck, and the alpaca was observed for discomfort symptoms 1 hour after immunization.

5.1.3 Blood Collection: Blood was collected before immunization, and kept as a negative control. After the third and fourth immunization, 5ml titer of blood was measured at intervals of one week, and the serum titer was detected by ELISA, and the titer met the requirements > 10⁵. KMD Bioscience provides customers with a clear information table of immunization time nodes, as shown in Table 1:

Table 1: Example of immune time course of generation of nanobody

KMD Bioscience has a large alpaca breeding base in northwest China. The company provides 200+ alpaca Nanobody generation services for scientific research users every year, and the generation cycle is short. It takes about 16-20 weeks to obtain high-quality library and monoclonal antibody cell lines, and can deliver 2ml VHH antibody library with a library capacity of 10⁸-10⁹. Welcome scientific research users to contact us.