Stability of anti-drug antibodies in human serum samples.

Stability of anti-drug antibodies (ADAs) is important as ADA-analysis should be reliable over time at different storage conditions. Stability of anti-insulin antibodies in serum samples was assessed after short-term storage at different temperatures and after long-term storage at -20 °C. Correlation between measurements was tested and acceptance criteria for incurred sample reanalysis were applied. ADAs were stable after 72 h at 22 °C, after 2 weeks at 4 °C, and after 6.3 years at -20 °C. The study confirms that ADAs in serum are stable for several years at -20 °C and suggests that investigation of short- and long-term stability of ADAs is not needed if samples are handled at standard laboratory-conditions.

Induction of CD8+ immune memory and enhanced inflammation in a skin inflammation model through pre-immunization with inactivated pathogens.

Laboratory mice live in specific pathogen-free (SPF) conditions, resulting in an immature immune system comparable to that of newborns rather than adult humans or mice from pet shops. This condition may compromise their translational value. Reintroducing pathogens would lead to the uncontrolled spread of infections and associated diseases, so research facilities should seek safer alternatives. We immunized laboratory mice with a cocktail of pathogens, which were inactivated by ultraviolet irradiation and mixed with the adjuvant AddaVax. This immunization resulted in a higher percentage of CD8+ effector memory T cells compared to untreated mice, although the response was not as robust as in pet shop mice. In a model of skin inflammation, pre-immunization led to an increased skin inflammatory response compared to non-immunized mice. All immunized mice seroconverted to the pathogens in the mixture, while none of the non-immunized mice housed together seroconverted to the pathogens applied to the pre-immunized mice. In conclusion, pre-immunization of mice impacts the immune system, which includes increasing the levels of CD8+ effector memory T cells.

Rational design of a JAK1-selective siRNA inhibitor for the modulation of autoimmunity in the skin.

Inhibition of Janus kinase (JAK) family enzymes is a popular strategy for treating inflammatory and autoimmune skin diseases. In the clinic, small molecule JAK inhibitors show distinct efficacy and safety profiles, likely reflecting variable selectivity for JAK subtypes. Absolute JAK subtype selectivity has not yet been achieved. Here, we rationally design small interfering RNAs (siRNAs) that offer sequence-specific gene silencing of JAK1, narrowing the spectrum of action on JAK-dependent cytokine signaling to maintain efficacy and improve safety. Our fully chemically modified siRNA supports efficient silencing of JAK1 expression in human skin explant and modulation of JAK1-dependent inflammatory signaling. A single injection into mouse skin enables five weeks of duration of effect. In a mouse model of vitiligo, local administration of the JAK1 siRNA significantly reduces skin infiltration of autoreactive CD8+ T cells and prevents epidermal depigmentation. This work establishes a path toward siRNA treatments as a new class of therapeutic modality for inflammatory and autoimmune skin diseases.

In vitro and in vivo immunogenicity assessment of protein aggregate characteristics.

The immunogenicity risk of therapeutic protein aggregates has been extensively investigated over the past decades. While it is established that not all aggregates are equally immunogenic, the specific aggregate characteristics, which are most likely to induce an immune response, remain ambiguous. The aim of this study was to perform comprehensive in vitro and in vivo immunogenicity assessment of human insulin aggregates varying in size, structure and chemical modifications, while keeping other morphological characteristics constant. We found that flexible aggregates with highly altered secondary structure were most immunogenic in all setups, while compact aggregates with native-like structure were found to be immunogenic primarily in vivo. Moreover, sub-visible (1-100 µm) aggregates were found to be more immunogenic than sub-micron (0.1-1 µm) aggregates, while chemical modifications (deamidation, ethylation and covalent dimers) were not found to have any measurable impact on immunogenicity. The findings highlight the importance of utilizing aggregates varying in few characteristics for assessment of immunogenicity risk of specific morphological features and may provide a workflow for reliable particle analysis in biotherapeutics.

Influence of Production Process and Scale on Quality of Polypeptide Drugs: a Case Study on GLP-1 Analogs.

PURPOSE: Manufacturing processes for polypeptide/protein drugs are designed to ensure robust quality, efficacy and safety. Process differences introduced by follow-on manufacturers may result in changes in quality and clinical outcomes. This study investigated the impact of production methods on the stability and impurities of liraglutide and semaglutide drug substances/products, and the potential impact on drug quality, efficacy and safety. METHODS: State-of-the-art analytical methods were used to compare physical and chemical stability, and impurity profiles of drug substances/products from different suppliers. Identified polypeptide-related impurities were evaluated for immunogenicity potential by in silico T cell epitope prediction. Semaglutide immunogenicity in clinical trials (SUSTAIN) was evaluated using a tiered antibody analysis. RESULTS: Manufacturing scale and process strongly impacted the physical stability of the products. Trace metals increased high-molecular-weight protein formation for liraglutide and semaglutide. Synthetic and recombinant liraglutide produced by five suppliers had distinct impurity profiles compared with the originator. In silico evaluation suggested that new impurities could be immunogenic. Immunogenicity of semaglutide in clinical trials was lower than for liraglutide. CONCLUSIONS: Differences in manufacturing processes affect chemical/physical stability and impurity profile, and may impact immunogenicity. Follow-on versions of liraglutide and semaglutide, and possibly other polypeptides, should be clinically evaluated for efficacy and safety.

Qualitative and quantitative analysis of adenovirus type 5 vector-induced memory CD8 T cells: not as bad as their reputation.

It has been reported that adenovirus (Ad)-primed CD8 T cells may display a distinct and partially exhausted phenotype. Given the practical implications of this claim, we decided to analyze in detail the quality of Ad-primed CD8 T cells by directly comparing these cells to CD8 T cells induced through infection with lymphocytic choriomeningitis virus (LCMV). We found that localized immunization with intermediate doses of Ad vector induces a moderate number of functional CD8 T cells which qualitatively match those found in LCMV-infected mice. The numbers of these cells may be efficiently increased by additional adenoviral boosting, and, importantly, the generated secondary memory cells cannot be qualitatively differentiated from those induced by primary infection with replicating virus. Quantitatively, DNA priming prior to Ad vaccination led to even higher numbers of memory cells. In this case, the vaccination led to the generation of a population of memory cells characterized by relatively low CD27 expression and high CD127 and killer cell lectin-like receptor subfamily G member 1 (KLRG1) expression. These memory CD8 T cells were capable of proliferating in response to viral challenge and protecting against infection with live virus. Furthermore, viral challenge was followed by sustained expansion of the memory CD8 T-cell population, and the generated memory cells did not appear to have been driven toward exhaustive differentiation. Based on these findings, we suggest that adenovirus-based prime-boost regimens (including Ad serotype 5 [Ad5] and Ad5-like vectors) represent an effective means to induce a substantially expanded, long-lived population of high-quality transgene-specific memory CD8 T cells.

The role of CD80/CD86 in generation and maintenance of functional virus-specific CD8+ T cells in mice infected with lymphocytic choriomeningitis virus.

Lymphocytic choriomeningitis virus (LCMV)-specific CD8(+) T cell responses are considered to be independent of CD28-B7 costimulation. However, the LCMV-specific response has never been evaluated in B7.1/B7.2(-/-) mice. For this reason, we decided to study the T cell response in B7.1/B7.2(-/-) mice infected with two different strains of LCMV, one (Traub strain) typically causing low-grade chronic infection, and another (Armstrong clone 53b) displaying very limited capacity for establishing chronic infection. Using Traub virus we found that most B7.1/B7.2(-/-) mice were unable to rid themselves of the infection. Chronic infection was associated with a perturbed CD8(+) T cell epitope hierarchy, as well as with the accumulation of cells expressing markers of terminal differentiation and being unable to respond optimally to Ag restimulation. Examination of matched CD28(-/-) mice revealed a similar albeit less pronounced pattern of CD8(+) T cell dysfunction despite lack of virus persistence. Finally, analysis of B7.1/B7.2(-/-) mice infected with Armstrong virus revealed a scenario quite similar to that in Traub infected CD28(-/-) mice; that is, the mice displayed evidence of T cell dysfunction, but no chronic infection. Taken together, these results indicate that B7 costimulation is required for induction and maintenance of LCMV-specific CD8(+) T cell memory, irrespective of the LCMV strain used for priming. However, the erosion of CD8(+) T cell memory in B7.1/B7.2(-/-) mice was more pronounced in association with chronic infection. Finally, virus-specific T cell memory was more impaired in the absence of B7 molecules than in the absence of the CD28 receptor, supporting earlier data suggesting the existence of additional stimulatory receptors for B7.

T-cell intrinsic expression of MyD88 is required for sustained expansion of the virus-specific CD8+ T-cell population in LCMV-infected mice.

Acute infection with lymphocytic choriomeningitis virus (LCMV) normally results in robust clonal expansion of virus-specific CD8(+) T cells, which in turn control the primary infection. However, similar infection of myeloid differentiation factor 88 (MyD88)-deficient mice leads to a markedly impaired T-cell response and chronic infection. It has been found previously that impairment of the innate immune response is not sufficient to explain this profound change in outcome. Using adoptive transfer of CD8(+) T cells, this study demonstrated unequivocally that T-cell expression of MyD88 is critical for a normal T-cell response to LCMV. In addition, it was found that expression of MyD88 is superfluous during early activation and proliferation of the antigen-activated CD8(+) T cells, but plays a critical role in the sustained expansion of the antigen-specific CD8(+) T-cell population during the primary T-cell response. Interestingly, a critical role for MyD88 was evident only under conditions of systemic infection with virus capable of causing prolonged infection, suggesting that MyD88 expression may function as an internal regulator of the threshold for antigen-driven, exhaustive differentiation.

TLR2 and TLR9 synergistically control herpes simplex virus infection in the brain.

Viruses are recognized by the innate immune system through pattern recognition receptors (PRRs). For instance, HSV virions and genomic DNA are recognized by TLR2 and TLR9, respectively. Although several viruses and viral components have been shown to stimulate cells through TLRs, only very few studies have defined essential roles for single TLRs in innate immune defense in vivo. This could suggest that PRRs act in concert to mount the first line of defense against virus infections. To test this hypothesis we have examined the host response of C57BL/6, TLR2(-/-), TLR9(-/-), and TLR2/9(-/-) mice toward HSV-2 infection. After a systemic infection, the cytokine serum response was markedly reduced in the double knockout mice, but only partly affected in either strain of the single knockout mice. This was supported by in vitro data showing that HSV-induced cytokine expression relayed on TLR2 and TLR9 in a cytokine- and cell type-dependent manner. With respect to the cellular response to infection, we found that recruitment but not activation of NK cells was impaired in TLR2/9(-/-) mice. Importantly, the viral load in the brain, but not liver, was significantly higher in the brain of TLR2/9(-/-) mice whereas the viral loads in organs of single knockout mice were statistically indistinguishable from C57BL/6 mice. In the brain we found that TNF-alpha and the IFN-stimulated gene CXCL9 were expressed during infection and were dependent on either TLR2 or TLR9. Thus, TLR2 and TLR9 synergistically stimulate innate antiviral activities, thereby protecting against HSV infection in the brain.

An important role for type III interferon (IFN-lambda/IL-28) in TLR-induced antiviral activity.

Type III IFNs (IFN-lambda/IL-28/29) are cytokines with type I IFN-like antiviral activities, which remain poorly characterized. We herein show that most cell types expressed both types I and III IFNs after TLR stimulation or virus infection, whereas the ability of cells to respond to IFN-lambda was restricted to a narrow subset of cells, including plasmacytoid dendritic cells and epithelial cells. To examine the role of type III IFN in antiviral defense, we generated IL-28Ralpha-deficient mice. These mice were indistinguishable from wild-type mice with respect to clearance of a panel of different viruses, whereas mice lacking the type I IFN receptor (IFNAR(-/-)) were significantly impaired. However, the strong antiviral activity evoked by treatment of mice with TLR3 or TLR9 agonists was significantly reduced in both IL-28RA(-/-) and IFNAR(-/-) mice. The type I IFN receptor system has been shown to mediate positive feedback on IFN-alphabeta expression, and we found that the type I IFN receptor system also mediates positive feedback on IFN-lambda expression, whereas IL-28Ralpha signaling does not provide feedback on either type I or type III IFN expression in vivo. Finally, using bone-marrow chimeric mice we showed that TLR-activated antiviral defense requires expression of IL-28Ralpha only on nonhemopoietic cells. In this compartment, epithelial cells responded to IFN-lambda and directly restricted virus replication. Our data suggest type III IFN to target a specific subset of cells and to contribute to the antiviral response evoked by TLRs.

Rapid and sustained CD4(+) T-cell-independent immunity from adenovirus-encoded vaccine antigens.

Many novel vaccine strategies rely on recombinant viral vectors for antigen delivery, and adenovirus vectors have emerged among the most potent of these. In this report, we have compared the immune response induced through priming with adenovirus vector-encoded full-length viral protein to that elicited with an adenovirus-encoded minimal epitope covalently linked to beta(2)-microglobulin. We demonstrate that the beta(2)-microglobulin-linked epitope induced an accelerated and augmented CD8(+) T-cell response. Furthermore, the immunity conferred by vaccination with beta(2)-microglobulin-linked lymphocytic choriomeningitis virus (LCMV)-derived epitopes was long-lived and protective. Notably, in contrast to full-length protein, the response elicited with the beta(2)-microglobulin-linked LCMV-derived epitope was CD4(+) T-cell independent. Furthermore, virus-specific CD8(+) T cells primed in the absence of CD4(+) T-cell help were sustained in the long term and able to expand and control a secondary challenge with LCMV. Our results demonstrate that modifications to the antigen used in adenovirus vaccines may be used to improve the induced T-cell response. Such a strategy for CD4(+) T-cell-independent immunity from adenovirus vectors offers prospects for vaccination against opportunistic pathogens in AIDS patients and possibly immunotherapy in chronic virus infections.

Agonistic anti-CD40 antibody profoundly suppresses the immune response to infection with lymphocytic choriomeningitis virus.

Previous work has shown that agonistic Abs to CD40 (anti-CD40) can boost weak CD8 T cell responses as well as substitute for CD4 T cell function during chronic gammaherpes virus infection. Agonistic anti-CD40 treatment has, therefore, been suggested as a potential therapeutic strategy in immunocompromised patients. In this study, we investigated whether agonistic anti-CD40 could substitute for CD4 T cell help in generating a sustained CD8 T cell response and prevent viral recrudescence following infection with lymphocytic choriomeningitis virus (LCMV). Contrary to expectations, we found that anti-CD40 treatment of MHC class II-deficient mice infected with a moderate dose of LCMV resulted in severe suppression of the antiviral CD8 T cell response and uncontrolled virus spread, rather than improved CD8 T cell immune surveillance. In Ab-treated wild-type mice, the antiviral CD8 T cell response also collapsed prematurely, and virus clearance was delayed. Additional analysis revealed that, following anti-CD40 treatment, the virus-specific CD8 T cells initially proliferated normally, but an increased cell loss compared with that in untreated mice was observed. The anti-CD40-induced abortion of virus-specific CD8 T cells during LCMV infection was IL-12 independent, but depended partly on Fas expression. Notably, similar anti-CD40 treatment of vesicular stomatitis virus-infected mice resulted in an improved antiviral CD8 T cell response, demonstrating that the effect of anti-CD40 treatment varies with the virus infection studied. For this reason, we recommend further evaluation of the safety of this regimen before being applied to human patients.

Lambda interferon (IFN-lambda), a type III IFN, is induced by viruses and IFNs and displays potent antiviral activity against select virus infections in vivo.

Type III interferons (IFNs) (interleukin-28/29 or lambda interferon [IFN-lambda]) are cytokines with IFN-like activities. Here we show that several classes of viruses induce expression of IFN-lambda1 and -lambda2/3 in similar patterns. The IFN-lambdas were-unlike alpha/beta interferon (IFN-alpha/beta)-induced directly by stimulation with IFN-alpha or -lambda, thus identifying type III IFNs as IFN-stimulated genes. In vitro assays revealed that IFN-lambdas have appreciable antiviral activity against encephalomyocarditis virus (EMCV) but limited activity against herpes simplex virus type 2 (HSV-2), whereas IFN-alpha potently restricted both viruses. Using three murine models for generalized virus infections, we found that while recombinant IFN-alpha reduced the viral load after infection with EMCV, lymphocytic choriomeningitis virus (LCMV), and HSV-2, treatment with recombinant IFN-lambda in vivo did not affect viral load after infection with EMCV or LCMV but did reduce the hepatic viral titer of HSV-2. In a model for a localized HSV-2 infection, we further found that IFN-lambda completely blocked virus replication in the vaginal mucosa and totally prevented development of disease, in contrast to IFN-alpha, which had a more modest antiviral activity. Finally, pretreatment with IFN-lambda enhanced the levels of IFN-gamma in serum after HSV-2 infection. Thus, type III IFNs are expressed in response to most viruses and display potent antiviral activity in vivo against select viruses. The discrepancy between the observed antiviral activity in vitro and in vivo may suggest that IFN-lambda exerts a significant portion of its antiviral activity in vivo via stimulation of the immune system rather than through induction of the antiviral state.

Perforin-deficient CD8+ T cells mediate fatal lymphocytic choriomeningitis despite impaired cytokine production.

Intracerebral (i.c.) infection with lymphocytic choriomeningitis virus (LCMV) is one of the most studied models for virus-induced immunopathology, and based on results from perforin-deficient mice, it is currently assumed that fatal disease directly reflects perforin-mediated cell lysis. However, recent studies have revealed additional functional defects within the effector T cells of LCMV-infected perforin-deficient mice, raising the possibility that perforin may not be directly involved in mediating lethal disease. For this reason, we decided to reevaluate the role of perforin in determining the outcome of i.c. infection with LCMV. We confirmed that the expansion of virus-specific CD8(+) T cells is unimpaired in perforin-deficient mice. However, despite the fact that the virus-specific CD8(+) effector T cells in perforin-deficient mice are broadly impaired in their effector function, these mice invariably succumb to i.c. infection with LCMV strain Armstrong, although a few days later than matched wild-type mice. Upon further investigation, we found that this delay correlates with the delayed recruitment of inflammatory cells to the central nervous system (CNS). However, CD8(+) effector T cells were not kept from the CNS by sequestering in infected extraneural organ sites such as liver or lungs. Thus, the observed dysfunctionality regarding the production of proinflammatory mediators probably results in the delayed recruitment of effector cells to the CNS, and this appears to be the main explanation for the delayed onset of fatal disease in perforin-deficient mice. However, once accumulated in the CNS, virus-specific CD8(+) T cells can induce fatal CNS pathology despite the absence of perforin-mediated lysis and reduced capacity to produce several key cytokines.

Impaired virus control and severe CD8+ T-cell-mediated immunopathology in chimeric mice deficient in gamma interferon receptor expression on both parenchymal and hematopoietic cells.

Bone marrow chimeras were used to determine the cellular target(s) for the antiviral activity of gamma interferon (IFN-gamma). By transfusing such mice with high numbers of naive virus-specific CD8(+) T cells, a system was created in which the majority of virus-specific CD8(+) T cells would be capable of responding to IFN-gamma, but expression of the relevant receptor on non-T cells could be experimentally controlled. Only when the IFN-gamma receptor is absent on both radioresistant parenchymal and bone marrow-derived cells will chimeric mice challenged with a highly invasive, noncytolytic virus completely lack the ability to control the infection and develop severe wasting disease. Further, the study shows that IFN-gamma receptor expression on parenchymal cells in the viscera is more important for virus control than IFN-gamma receptor expression on bone marrow-derived cells.

Single-epitope DNA vaccination prevents exhaustion and facilitates a broad antiviral CD8+ T cell response during chronic viral infection.

Induction of a monospecific antiviral CD8+ T cell response may pose a risk to the host due to the narrow T cell response induced. At the individual level, this may result in selection of CD8+ T cell escape variants, particularly during chronic viral infection. Second, prior immunization toward a single dominant epitope may suppress the response to other viral epitopes, and this may lead to increased susceptibility to reinfection with escape variants circulating in the host population. To address these issues, we induced a memory response consisting solely of monospecific, CD8+ T cells by use of DNA vaccines encoding immunodominant epitopes of lymphocytic choriomeningitis virus (LCMV). We analyzed the spectrum of the CD8+ T cell response and the susceptibility to infection in H-2(b) and H-2(d) mice. Priming for a monospecific, CD8+ T cell response did not render mice susceptible to viral variants. Thus, vaccinated mice were protected against chronic infection with LCMV, and no evidence indicating biologically relevant viral escape was obtained. In parallel, a broad and sustained CD8+ T cell response was generated upon infection, and in H-2(d) mice epitope spreading was observed. Even after acute LCMV infection, DNA vaccination did not significantly impair naturally induced immunity. Thus, the response to the other immunogenic epitopes was not dramatically suppressed in DNA-immunized mice undergoing normal immunizing infection, and the majority of mice were protected against rechallenge with escape variants. These findings underscore that a monospecific vaccine may induce efficient protective immunity given the right set of circumstances.

Gene-gun DNA vaccination aggravates respiratory syncytial virus-induced pneumonitis.

A CD8+ T-cell memory response to respiratory syncytial virus (RSV) was generated by using a DNA vaccine construct encoding the dominant Kd-restricted epitope from the viral transcription anti-terminator protein M2 (M2(82-90)), linked covalently to human beta2-microglobulin (beta2m). Cutaneous gene-gun immunization of BALB/c mice with this construct induced an antigen-specific CD8+ T-cell memory. After intranasal RSV challenge, accelerated CD8+ T-cell responses were observed in pulmonary lymph nodes and virus clearance from the lungs was enhanced. The construct induced weaker CD8+ T-cell responses than those elicited with recombinant vaccinia virus expressing the complete RSV M2 protein, but stronger than those induced by a similar DNA construct without the beta2m gene. DNA vaccination led to enhanced pulmonary disease after RSV challenge, with increased weight loss and cell recruitment to the lung. Depletion of CD8+ T cells reduced, but did not abolish, enhancement of disease. Mice vaccinated with a construct encoding a class I-restricted lymphocytic choriomeningitis virus epitope and beta2m suffered more severe weight loss after RSV infection than unvaccinated RSV-infected mice, although RSV-specific CD8+ T-cell responses were not induced. Thus, in addition to specific CD8+ T cell-mediated immunopathology, gene-gun DNA vaccination causes non-specific enhancement of RSV disease without affecting virus clearance.

Incomplete effector/memory differentiation of antigen-primed CD8+ T cells in gene gun DNA-vaccinated mice.

DNA vaccination is an efficient way to induce CD8+ T cell memory, but it is still unclear to what extent such memory responses afford protection in vivo. To study this, we induced CD8+ memory responses directed towards defined viral epitopes, using DNA vaccines encoding immunodominant MHC class I-restricted epitopes of lymphocytic choriomeningitis virus covalently linked to beta2-microglobulin. This vaccine construct primed for a stronger recall response than did a more conventional minigene construct. Despite this, vaccinated mice were only protected against systemic infection whereas protection against the consequences of peripheral challenge was limited. Phenotypic analysis revealed that DNA vaccine-primed CD8+ T cells in uninfected mice differed from virus-primed CD8+ T cells particularly regarding expression of very-late antigen (VLA)-4, an adhesion molecule important for targeting T cells to inflammatory sites. Thus, our DNA vaccine induces a long-lived memory CD8+ T cell population that provides efficient protection against high-dose systemic infection. However, viral replication in solid non-lymphoid organs is not curtailed sufficiently fast to prevent significant virus-induced inflammation. Our results suggest that this is due to qualitative limitations of the primed CD8+ T cells.

The virus-encoded chemokine vMIP-II inhibits virus-induced Tc1-driven inflammation.

The human herpesvirus 8-encoded protein vMIP-II is a potent in vitro antagonist of many chemokine receptors believed to be associated with attraction of T cells with a type 1 cytokine profile. For the present report we have studied the in vivo potential of this viral chemokine antagonist to inhibit virus-induced T-cell-mediated inflammation. This was done by use of the well-established model system murine lymphocytic choriomeningitis virus infection. Mice were infected in the footpad, and the induced CD8(+) T-cell-dependent inflammation was evaluated in mice subjected to treatment with vMIP-II. We found that inflammation was markedly inhibited in mice treated during the efferent phase of the antiviral immune response. In vitro studies revealed that vMIP-II inhibited chemokine-induced migration of activated CD8(+) T cells, but not T-cell-target cell contact, granule exocytosis, or cytokine release. Consistent with these in vitro findings treatment with vMIP-II inhibited the adoptive transfer of a virus-specific delayed-type hypersensitivity response in vivo, but only when antigen-primed donor cells were transferred via the intravenous route and required to migrate actively, not when the cells were injected directly into the test site. In contrast to the marked inhibition of the effector phase, the presence of vMIP-II during the afferent phase of the immune response did not result in significant suppression of virus-induced inflammation. Taken together, these results indicate that chemokine-induced signals are pivotal in directing antiviral effector cells toward virus-infected organ sites and that vMIP-II is a potent inhibitor of type 1 T-cell-mediated inflammation.

Regulation of T cell migration during viral infection: role of adhesion molecules and chemokines.

T cell mediated immunity and in particular CD8+ T cells are pivotal for the control of most viral infections. T cells exclusively exert their antiviral effect through close cellular interaction with relevant virus-infected target cells in vivo. It is therefore imperative that efficient mechanisms exist, which will rapidly direct newly generated effector T cells to sites of viral replication. In the present report we have reviewed our present knowledge concerning the molecular interactions, which are important in targeting of effector CD8+ T cells to sites of viral infection.