Interactions with charged surfaces affect antibody behavior

Immunoglobulins, or antibodies, are proteins that play a vital role in the immune system. However, when encountered by nanocarriers designed to transport medication into the body, immunoglobulins may recognize the nanocarriers as foreign compounds and set off immune reactions such as allergic responses or inflammation. To help identify and mitigate these unwanted reactions, Prozeller et al. studied the interactions between nanocarriers and different types of immunoglobulins responsible for different immune functions.

“The aim was to see the effect of the differently charged surfaces on the potential adverse effects and how the immunoglobulins react differently to the charges,” said author Svenja Morsbach.

According to the group’s findings, immunoglobulins and nanocarriers each impact the properties of the other, and every combination may exhibit behaviors drastically different from the next. However, they were able to conclude that charged nanocarriers are generally more problematic for the immune system than nanocarriers with overall neutral surface charge, which display fewer unfavorable interactions. Interactions with charged nanocarriers are also more likely to lead to denaturation, or structural changes in the immunoglobulin, and subsequent aggregation.

“In that case, a patient might not get the desired treatment, but actually experience side effects like inflammatory reactions,” Morsbach said.

To observe these reactions, the authors mixed nanocarriers with different charges into three types of human immunoglobulin solutions. In their current state, the nanocarriers are model systems not suitable for medical applications, though they help to provide insight on ideal protocols.

“We can say that generally unspecific immunoglobulin adsorption on nanocarriers should be decreased as much as possible because of the potential denaturation and its implications,” said Morsbach.

Source: “Immunoglobulins on the surface of differently charged polymer nanoparticles,” by Domenik Prozeller, Christine Rosenauer, Svenja Morsbach, and Katharina Landfester, Biointerphases (2020). The article can be accessed at https://doi.org/10.1116/6.0000139 .