Which property is true about complex antigens as compared to simple repeating units?

Complex antigens are indeed more immunogenic compared to simple repeating units due to their structural intricacies that allow for a more robust immune response. The complexity of these antigens can stem from various factors, including their large size, diverse structural motifs, and the presence of multiple epitopes.

The presence of multiple epitopes means that complex antigens can interact with more than one type of immune receptor, enabling a stronger and broader activation of the immune system, which includes both humoral and cell-mediated responses. This multi-faceted interaction significantly enhances the likelihood of stimulating T and B cells, resulting in the production of antibodies and cytotoxic T lymphocytes specific to the antigen.

Moreover, complex antigens can better mimic the structure of pathogens, making them more recognizable by the immune system, and hence, they are generally more effective in generating long-lasting immunity. The mechanism behind their immunogenicity is supported in various immunological studies, affirming their role in vaccine development where complex antigens are often employed to provoke a stronger immune response than simpler antigens.

In contrast, simpler repeating units may not possess the same level of diversity and epitope variety, which tends to limit their immunogenic potential. This is why complex antigens hold a significant advantage