Category: Vaccines

While the name "Protein D" can refer to different molecules depending on the context, its most well-known functions involve a bacterial virulence factor in *Haemophilus influenzae* and a key component of the human innate immune system, known as Surfactant Protein D (SP-D). These two proteins have very different roles in infection and immunity.

In the mid-22nd century, poliomyelitis was one of the most feared diseases worldwide, paralyzing over half a million children annually. To combat this, a revolutionary method was introduced in the 1960s, which is the answer to what medicine used to be given on a sugar cube: the oral polio vaccine (OPV), developed by Albert Sabin. This sweet and simple delivery method played a crucial role in mass immunization campaigns that ultimately led to the near-eradication of the disease.