Vaccinology and Applied Microbiology

Vaccination is the most efficient strategy to prevent infectious diseases. The art of the vaccine researcher lies in finding substances that prevent us from falling ill with diseases such as influenza or viral hepatitis. But what makes a vaccine successful and ensures effective protection? Our scientists study the reaction of the immune system to answer that question – and to develop better vaccination strategies.

Prof Dr Carlos A. Guzmán


Prof Dr Carlos A. Guzmán
Head of Research Group

Our Research

The use of vaccines is the most effective and inexpensive approach to promote protection against infectious diseases. Our vaccinologists are developing new vaccines, which can serve either as a prophylaxis or as a therapy against infections.

In order to achieve this goal, the scientists try to understand the host response mechanisms triggered by an infection or a vaccine in different subpopulation groups.

A strong immune response is not sufficient by itself for the success of the vaccination. The immune reaction must also fit well terms of effector mechanisms needed to achieve protection. How such a suitable response looks like can be learned from patients, who successfully combat an infection after triggering the appropriate effector mechanisms. Thus, the search begins at the hospital.

Our researchers also look for key new clinical markers that reveal how the patients’ immune system responds to the pathogen attack or to a vaccine in order to predict for vaccine efficacy and safety.

Within the last years the safety requirements for vaccines increased. Therefore, the so-called subunit vaccines were developed which consists only of selected antigens of a certain pathogen, instead of the whole pathogen itself. The disadvantage is that the immune response induced by these subunit vaccines is often not strong enough. Hence, excipients, so called adjuvants, need to be added. Our researchers identified promising adjuvants that promote the immune response and, in addition, allow its modulation and optimization. This will facilitate the development of a tailored vaccination strategy for each pathogen.

A successful vaccination strategy also includes the safe and simple delivery of the vaccines. The vision of our researchers: no longer to inject vaccines, but delivering them instead by a needle-free noninvasive approach. In this regard most of the pathogens attack the mucosal membranes. Thus, mucosal vaccination strategies, such as via a nasal spray or sublingual can stimulate the local mucosal immune system. As a result, the host develops local defensive mechanisms against the pathogen in the mucosal tissues as well as effector cells that disseminate throughout the entire body conferring protection. Special about this vaccination strategy is that already the entering of the pathogen via mucosal membranes can be blocked and the infection be prevented. In case of the conventional vaccination with a needle, no immune response at the mucosal membranes is induced and pathogens can still enter the body before the immune reaction starts (i.e. individuals might be protected against disease but they can still transfer the agent to other susceptible hosts).

Whether the vaccine is delivered via syringe or nasal spray – the development of any new vaccine requires extensive and prolonged research, including test series in preclinical models. However, despite of the high genetic similarity between animals and men, there are significant differences in the immune responses. For example, a vaccine which is successful in mice will not always be successful in humans. Thus, in order to increase the transferability of the obtained data into the human situation and to shorten the protracted and cost-intensive research phase vaccinologists develop new strategies. To this end, they evolve animal models based on mice which possess a humanized immune system. With this approach the research turns full circle: we return to the clinic. But this time not for the purpose of examining sick patients, but to prevent new illnesses.