Industry Insights with Amy Sheng on Nanobodies This episode of Share Science features Amy Sheng, PhD , a technical account manager at Sino Biological . In this interview, Amy shares how nanobodies are emerging as important tools for tumor diagnosis and treatment, and how they are expected to revolutionize antibody-based drug therapies for a wide range of pathological conditions and especially cancer immunotherapy. LISTEN TO THE PODCAST:

What are nanobodies and how are they used?

Nanobodies are single-domain antibodies that were discovered nearly 30 years ago. They're found in a lot of interesting animals such as alpacas, llamas, and cartilaginous fish like sharks and rays. Unlike traditional immunoglobulin-G antibodies from humans and mice that contain both heavy and light chains, nanobodies do not have light chains. Nanobodies bind to antigens through the single variable domain on a heavy chain (VHH). These single-domain antibodies with only VHH are currently the smallest naturally-derived antigen-binding fragments. That's where the name nanobody comes from and I guess anything smaller than that would be nobody. Their applications have been explored in a wide range of conditions such as neurological, infectious, and inflammatory diseases. I would also like to point out that they are widely used for tumor diagnosis and therapeutics. Besides treating human diseases, scientists also use nanobodies to detect and fight pathogens in agriculture. Moreover, some nanobodies are developed to detect small molecules for environmental monitoring.

What are the advantages of nanobodies over conventional antibodies?

There are many great advantages of nanobodies over the conventional ones which mainly come from their size and structure, as well as their development and production protocols. As we mentioned, the VHH is currently the smallest antigen-binding fragment. Due to their small size, nanobodies can penetrate tissues more efficiently and bind to antigens that are less accessible to conventional antibodies.

Nanobodies are less immunogenic in humans and more soluble and stable [than conventional antibodies].

Some nanobodies can bind to antigens at high temperatures, and some are functional in presence of ammonia, sunlight, or ethanol. These properties increase their shelf life and offer alternative delivery routes such as inhalation. From the production point of view, there is no need to sacrifice animals when developing nanobodies, and no need to pair variable fragment heavy and light chains since nanobodies contain only a single domain. Furthermore, since their folding and stability is less dependent on disulfide bond formation, many systems like Escherichia coli and plants can be used to express and produce nanobodies, which can greatly lower production costs.

How are nanobodies developed?

It all starts with animals.

We know that those single-domain antibodies are found in sharks and rays, but theyre really hard to catch. Most of the experiments are done on camels; some are immunized and some are not. If we start with an immunized alpaca, blood is collected from the animal first, from which messenger RNA is extracted to construct complementary DNA (cDNA) by reverse transcription polymerase chain reaction. The cDNA is then amplified to isolate the VHH genes that are to be incorporated into plasmids. Researchers construct the VHH library from bacteriophages and pan the library for a desired binder if theyre starting with a target protein. After good binders are obtained, we do sequencing and then reconstruct to express and purify them. The final nanobody products are, of course, validated in various assays to determine their stability, affinity, and specificity. [fusion_builder_column type="1_1" layout="1_1" align_self="auto" content_layout="column" align_content="flex-start" valign_content="flex-start" content_wrap="wrap" spacing="" center_content="no" column_tag="div" link="" target="_self" link_description="" min_height="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" sticky_display="normal,sticky" class="" id="" type_medium="" type_small="" order_medium="0" order_small="0" dimension_spacing_medium="" dimension_spacing_small="" dimension_spacing="" dimension_margin_medium="" dimension_margin_small="" margin_top="" margin_bottom="" padding_medium="" padding_small="" padding_top="" padding_right="" padding_bottom="" padding_left="" hover_type="none" border_sizes="" border_color="" border_style="solid" border_radius="" box_shadow="no" dimension_box_shadow="" box_shadow_blur="0" box_shadow_spread="0" box_shadow_color="" box_shadow_style="" z_index_subgroup="regular" z_index="" z_index_hover="" overflow="" background_type="single" gradient_start_color="" gradient_end_color="" gradient_start_position="0" gradient_end_position="100" gradient_type="linear" radial_direction="center center" linear_angle="180" background_color="" background_image="" background_image_id="" lazy_load="avada" skip_lazy_load="" background_position="left top" background_repeat="no-repeat" background_blend_mode="none" render_logics="" sticky="off" sticky_devices="small-visibili