Inhibitory Effects of Chlorella Extract on Airway Hyperresponsiveness and Airway Remodeling in a Murine Model of Asthma

Chlorella extract （CE） has been shown to induce production of T helper-1 cytokines, and regulate serum IgE levels in animal models of asthma. We aimed to evaluate whether CE could inhibit ovalbumin （OVA）-induced airway hyperresponsiveness （AHR） and airway remodeling in a murine model of asthma. Balb/c mice were allocated to four groups: a control group （no OVA exposure, not given CE）, a CE group （no OVA exposure, given CE）, an asthma group （sensitized/challenged with OVA, not given CE） and a CE＋asthma group （sensitized/challenged with OVA, given CE）. In the asthma and CE＋asthma groups, mice were sensitized with OVA on day 0 and day 12, and then challenged with OVA on three consecutive days. In the CE and CE＋asthma groups, the mice were given feed containing 2％ CE. We assessed AHR to methacholine, and analyzed bronchoalveolar lavage fluid （BALF）, serum, lung tissue and spleen cells. Administration of CE was associated with significantly lower AHR in OVA-sensitized and challenged mice. CE administration was also associated with marked reduction of total cells, eosinophils and T helper-2 cytokines （IL-4, IL-5 and IL-13） in BALF. In addition, administration of CE significantly decreased the numbers of periodic acid-Schiff （PAS）-positive cells in OVA-sensitized and challenged mice. Administration of CE also directly suppressed IL-4, IL-5 and IL-13 production in spleen cells of OVA-sensitized and challenged mice. These results indicate that CE can partly prevent AHR and airway remodeling in a murine model of asthma

Long-term follow-up of production of IgM and IgG antibodies against SARS-CoV-2 among patients with COVID-19

The patients diagnosed with coronavirus disease 2019 （COVID-19） produce IgM and IgG antibodies against severe acute respiratory syndrome coronavirus 2 （SARS-CoV-2）. However, the frequency and duration of antibody production still need to be fully understood. In the present study, we investigated the duration of antibody production after SARS-CoV-2 infection. The patients diagnosed with COVID-19 were monitored over twelve months for the production of SARS-CoV-2 IgM and IgG antibodies, and the characteristics of these patients were examined. Forty-five patients diagnosed with COVID-19 were enrolled, and thirty-four patients were followed up until they tested negative for SARS-CoV-2 IgM and IgG antibodies or up to twelve months after the date of a negative SARS-CoV-2 polymerase chain reaction （PCR） result. The positivity rates of SARS-CoV-2 IgM and IgG antibodies were 27.3％ and 68.2％ when SARS-CoV-2 PCR was negative, 20.6％ and 70.6％ after one month, 8.8％ and 52.9％ after three months, and 0.0％ and 14.7％ after six months, respectively. Moreover, we compared patients with milder conditions who did not require oxygen administration with those with severe conditions which required oxygen administration. The positivity rate of SARS-CoV-2 IgG antibodies was significantly higher in patients with severe conditions than in those with milder conditions on the date of a negative SARS-CoV-2 PCR result and after one month and three months, but not after six months. Patients with more severe COVID-19 produced more SARS-CoV-2 IgG antibodies. Moreover, it is suggested that the duration of IgG antibody production is independent of COVID-19 severity